Exchange recurring meetings got forwarded automatically to Attendees RRS feed

  • Question

  • Hello there,

    We are running Exchange 2016 CU2 and Outlook 2016. Currently more and more users have complained that their recurring meetings are getting automatically forwarded to attendees with no reason. Sometimes it's from organizer himself (or herself) and sometimes from one of attendees. Users told us that they didn't do anything with his or her calendar during that time. Some of the forwarding happened in early morning 2AM. We have created some test recurring meetings we can duplicate the issue as well.

    I just wondering if everyone experiences the same issue and know the possible cause for this. Any suggestion will be greatly appreciated.


    Thursday, March 9, 2017 5:21 PM


  • According to our extensive tests, it appears the issue has been fixed by iOS 10.3.3 though there is no release note mentioned the fix. Good job Apple. Microsoft PPS misled us on the issue as they told us the fix should be Exchange 2016 CU6. CU6 didn't address the issue.

    • Marked as answer by exadmin818 Monday, July 24, 2017 1:46 PM
    • Edited by exadmin818 Monday, July 24, 2017 1:54 PM
    Monday, July 24, 2017 1:46 PM

All replies

  • Do these folks all have their Exchange account set up on an iPhone/iPad with ActiveSync?
    Thursday, March 9, 2017 5:51 PM
  • The organizer has one android device. Yes of course, for now, everyone should have ActiveSync device.
    Thursday, March 9, 2017 8:28 PM
  • Can you see the forwarded message in the sent items in Outlook on the pc?

    Does the duplicate meetings showing in Outlook client on the pc?

    Friday, March 10, 2017 12:18 AM
  • Yes, the forwarded message is in sent items folder in Outlook PC. just one incident of the meetings is shown on all recipients' calendar with subject FW: Original _meeting_subject.

    I checked the EAS report that shows the sender's mobile didn't send any email during the time window (hourly report). sync folder once (because of the sent item sync).The meeting was forwarded by the organizer four times on the President holiday. he mentioned he was watching movie at home at times the meeting requests were forwarded, never touched his mobile device (Samsung S7).

    the meeting was forwarded four times:

    12:18 PM

    2:38 PM

    4:40 PM

    and 6:28 PM

    • Edited by exadmin818 Friday, March 10, 2017 1:18 AM corrected typo and povide more info
    Friday, March 10, 2017 1:14 AM
  • Is there a rule in his Outlook that does the forwarding?

    Try using message tracking log to see who sent it.

    Friday, March 10, 2017 2:17 AM
  • Hi Exadmin818,

    Except above suggestions, please check if the sender's mailbox has been granted full access permission or delegate additional permissions to someone else.

    If yes, we can remove these permission and check again.

    Best Regards,

    Niko Cheng
    TechNet Community Support

    Please remember to mark the replies as answers.
    If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    • Edited by Niko.Cheng Friday, March 10, 2017 8:30 AM
    Friday, March 10, 2017 8:29 AM
  • there is no rule that may cause the issue. I even run Outlook /cleanrules switch on my test account.

    here is messaging tracking log, it shows it is the organizer (ldavis@xyz.com) who sent the meeting (note:masked domain name for privacy):

    BTW, can the message tracking log tell which client that forwarded the meeting?


    RunspaceId              : 6986a8a0-d850-458f-8e80-2d4d2c6ff0c7
    Timestamp               : 2/20/2017 12:18:28 PM
    ClientIp                :
    ClientHostname          : USEX1MAIL-01.us.xyz.com
    ServerIp                :
    ServerHostname          : USEXMAIL-01
    SourceContext           : 08D4369597813ED4;2017-02-20T17:18:27.790Z;ClientSubmitTime:2017-02-20T17:18:20.916Z
    ConnectorId             :
    Source                  : STOREDRIVER
    EventId                 : DELIVER
    InternalMessageId       : 29965986825807
    MessageId               : <321b19d052674030970f18bb0eb44085@xyz.com>
    NetworkMessageId        : f0a8ac41-6f99-4ed6-c929-08d459b47832
    Recipients              : {msmith@xyz.com,afinn@xyz.com....}
    RecipientStatus         : {}
    TotalBytes              : 268942
    RecipientCount          : 1
    RelatedRecipientAddress :
    Reference               :
    MessageSubject          : FW: Run24 Meeting
    Sender                  : ldavis@xyz.com
    ReturnPath              : ldavis@xyz.com
    Directionality          : Originating
    TenantId                :
    OriginalClientIp        :
    MessageInfo             : 2017-02-20T17:18:20.916Z;SRV=USEXMAIL-03.us.xyz.com:TOTAL-SUB=0.864|SA=0.046|MTSS-PEN=0.819(MTSSD-PEN
                              =0.819(MTSSDA=0.003|MTSSDC=0.178|MTSSDSDM=0.375 (MTSSDSDM-Meeting Forward Notification
                              Agent=0.375)|SDSSO-PEN=0.244(SMSC=0.090|MTSSDM-PEN=0.153 )));SRV=USEX1MAIL-01.us.xyz.com:TOTAL-HUB=6.2
                              85|SMR=0.305(SMRDI=0.166|SMRC=0.138(SMRCL=0.104|X-SMRCR=0.140))|CAT=5.593(CATOS=0.001 (CATSM=0.001(CATSM-RMS
                              Decryption Agent=0.001))|CATRESL=0.010|CATORES=0.073(CATRS=0.073 (CATRS-Prioritization
                              Agent=0.001|CATRS-ScanMail Routing Agent=0.036|CATRS-Transport Rule Agent=0.014 |CATRS-Index Routing
                              Agent=0.019))|CATORT=5.505(CATRT=5.505(CATRT-CodeTwo Exchange Rules=5.151 |CATRT-Journal Agent=0.352)))|QDM=0.
                              =0.009|SDDPM=0.113(SDDPM-Conversations Processing Agent=0.101|SDDPM-Mailbox Rules Agent=0.009|SDDPM-Meeting
                              Message Processing Agent=0.002)|SDDCM=0.327(SDDCM-Meeting Message Processing
    MessageLatency          : 00:00:07.7490000
    MessageLatencyType      : EndToEnd
    EventData               : {[MailboxDatabaseGuid, 054f50e2-a0bc-47b8-a6f5-f3b74d4f63c8], [Mailboxes,
                              df413e68-9a80-47a7-a94e-cd664130dfd1], [StoreObjectIds,
                              [FromEntity, Hosted], [ToEntity, Hosted], [MsgRecipCount, 83], [SubRecipCount, 83], [AttachCount, 0],
                              [E2ELatency, 7.750], [DeliveryPriority, Normal], [AccountForest, xyz.com]}
    TransportTrafficType    : Email
    SchemaVersion           : 15.01.0466.033

    Friday, March 10, 2017 1:42 PM
  • there is no delegate permission setup on the organizer's mailbox. Thank you.

    Friday, March 10, 2017 1:44 PM
  • Not sure but I can see there's CodeTwo Exchange agent running, do you know what the agent is performing?

    What happen if you disable the CodeTwo Exchange agent?

    Monday, March 13, 2017 10:25 PM
  • Hi Michael,

    CodeTwo is auto response agent from CodeTwo which can only be triggered if we configure a specific mailbox with auto response message.


    Also I checked several Microsoft KBs. it seems Microsoft introduced new feature of Exchange EAS 16 that may cause the issue:

    The organizer of the meeting performed an action on his or her iOS 9.x device that sent a change for the appointment to Exchange. A new behavior was introduced in version 16 of the Exchange ActiveSync (EAS) protocol in which Exchange sends meeting updates when an EAS client sends a change for the appointment.

    This description about the action of organizer with IOS 9.x device. In our case the organizer is Samsung S7. and he didn't do anything on his phone during that times.

    We also have a report that a week ago that one of our Canada units, they sent a company-wide event to their users for one time meeting event. The organizer doesn't have any ActiveSync device, however, one of the recipients responded (accepted the meeting with comments to the organizer using her Desktop Outlook 2016, and system generated a duplicated new meeting request automatically with identical subject line and exact same meeting note (note: the meeting note format are slight different, the original meeting note text has colors) and the forwarder is becoming the organizer of the new meeting event.Note: the recipient, new meeting organizer does have activesync device but she installed Microsoft Outlook for IOS. and her iPhone IOS version is the latest one 10.2.1


    The above Microsoft KB latest revision is November, 2015. Note sure why Microsoft doesn't have any update since then. BTW, are you working for Microsoft? Is it possible to contact Microsoft inside, developers, for this?

    Thanks again. 

    PS: the CodeTwo should not cause the issue, since we just installed the CodeTwo recently and the behavior started happening after we migrated our Exchange 2016 CU1 summer. now CU2 for almost half year already.

    Tuesday, March 14, 2017 4:12 PM
  • Hi,

    I'm guessing you are using the native mail on the Samsung device right? If not, try using the native mail. 

    What happen if you try it out with IOS devices only?

    Can you update to the latest CU. 

    Tuesday, March 14, 2017 11:45 PM
  • The organizer is using native mail on Samsung device. BTW, we created new meeting, new organizer is my manager who has iPhone. He is using Outlook for IOS per Microsoft KB. The meeting was forwarded by one of attendees twice today automatically. users keep accepting the forward meeting. Organizer keep receiving such meeting "accepted" notification emails (there are about two hundred attendees). Actually there is no change at all for the meeting.

    We have tested it in the Lab. it still happens to CU4. BTW, CU4 causes other issue, users cannot change password via OWA for users domains that is not the same as Exchange installed domain (same Forest) :-(. with CU2, there is an option, go to earlier version (exchange 2013 version) and users can change password there with no problem. The features was removed by Microsoft after CU3.

    Wednesday, March 15, 2017 1:59 AM
  • Can you try this.

    1. Create a new EAS policy with same settings.

    2. enrol 3 test devices to the new EAS policy

    3. send meeting request from device 1 to the other 2 devices

    Let's see if the new policy has the same issue. This is basically isolating to determine if EAS policy has an issue or not.

    Thursday, March 16, 2017 2:36 AM
  • Thank you, will do.
    Monday, March 20, 2017 6:08 PM
  • Hello Michael,

    I created a new EAS policy and assigned test users to the EAS policy, create a new test meeting, the forwarding still happens.

    Thanks again.

    Thursday, March 23, 2017 6:34 PM
  • upgrade Lab to CU 5, we still have meeting auto forwarding issues...
    Tuesday, March 28, 2017 3:28 PM
  • Sound like a known bug. I would suggest to log a job with PSS.
    Thursday, March 30, 2017 11:22 PM
  • We have opened a PSS case with Microsoft for several months already. They have not provided much valuable info. I post the issue here and hope Microsoft develop team can jump in to look at the case. It seems the issue has been around for several years. Microsoft blames it's Apple app issue and Apple says it's Microsoft activesync bug with no solution.
    Friday, March 31, 2017 3:23 PM
  • Do you have a Windows phone? If so, then try it out and see if it's an IOS device that is the cause of the problem.
    Monday, April 3, 2017 3:20 AM
  • I'm having this issue and it's gotten a lot worse lately.  We're on Exchange 2016 CU3 on premise.  Lots of Windows computers, Mac computers, iPhones and Androids.  Can't find a common thread among all of the people who are sending forwards when they weren't even at a computer and didn't do anything on their phone, but it does seem to occur more on recurring meetings.  Has anyone heard any news on this?

    Crystal Marks Sr. Exchange Administrator

    Wednesday, April 5, 2017 7:01 PM
  • Actually, we have opened support case with Microsoft for a while (more than 6 months from now). We have tested with CU5 (released last month) in lab, the issue still exists. Finally Microsoft support engineer was able to speak with their developer team who admitted it's Microsoft ActiveSync bug that has not addressed in CU5 yet, will be fixed in CU6 ( let us cross our fingers).  
    Thursday, April 6, 2017 1:15 PM
  • So I'm in the early stages of a case that I opened last week and the guy is telling me there is no known issue with Activesync and that this is probably related to Outlook rules.  I called BS on him after he wasted an hour of my time yesterday trying to walk me through wiping all of my rules when the incident is not only happening to me, and there is no way we can test it afterwards unless we do this to every user who we've seen this happen to and wait for it to happen again.  Just such a drag to get the runaround from them on something they appear to have done zero research on for my call.

    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, April 12, 2017 1:53 PM
  • Hi Crystal,

    We did outlook /cleanrules as well, it won't help. It's kind of easy to duplicate the issue:

    create a recurring meeting, add test attendees.

    once meeting pop up, from attendee's iPhone, swipe it down, and choose snooze... the forwarding may be not generated right away, it could be generated at mid night. Currently one of users complained that she even didn't touch her phone, she just clicked snooze from her PC Outlook (2016) and it generated auto forwarding as well.

    Wednesday, April 12, 2017 2:11 PM
  • Thank you for the additional info, that will be interesting to try.

    Our users sometimes generate dozens of forwards at a time or over several hours.  One day it was me while I was out of the office, and today the random user that is "forwarding meetings on behalf of the organizer" is also out of the office.  He probably did hit snooze or dismiss on the meeting from his iphone, but there are about 40 people on the meeting and it is only happens with one person randomly each week.  Does it only happen with users who sync with an Apple device?


    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, April 12, 2017 2:21 PM
  • yes, we had the exact the same issue. It seems it happened to users who have Apple devices and Android device (one case) who is the organizer. For android case, the meeting has about 200 attendees. Majority of them are volunteers who usually do not attend the meeting, once meeting reminder is popped up, usually they just dismiss it. sometimes they hit by mistake "snooze" instead that cause the forwarding. Sometimes, it sends right away. sometimes, it sends with delays. some of them were sent at 2AM, 3AM. Once it was forwarded, it usually generated more than one forwarding meetings with different time randomly. If the one of attendees forwarded the meeting, recipients received as the attendee forwarded the meeting on behalf of the organizer and the organizer will notifications of the meeting forwarding. Other attendees may accept the new meeting for one instance, never in series, and the organizer may get more than hundred of such meeting acceptance notifications. that's absolutely not fun!
    Wednesday, April 12, 2017 2:46 PM
  • Wow, it's really nice to get more data on this, thank you.  In our case I know I hit "dismiss' on meetings when I'm out of the office, not snooze, so I wonder if that also causes it.  And strangely today, the forwards started coming in long before the meeting notification time...so the meeting is at 10, the reminder is 15 minutes early and the forwards started over an hour beforehand.  I wish Microsoft would put some effort into this, we can't be the only people having this issue but it is very difficult to search for since the results get muddied up by meeting and delegate how-tos.  I really appreciate your responses.

    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, April 12, 2017 3:14 PM
  • try this cmdlet to see if you get any detailed info. it does not work for me though.

    get-CalendarDiagnosticLog -Subject "FW: The meeting subject of your case" -Identity "forwarduseralias@yourdomain.com"

    let me know.

    Wednesday, April 12, 2017 4:32 PM
  • I ran this on the user who is generating a lot of forwards today and is out of the office...it came back with dozens of these with different time stamps that probably correspond with the forwards even though the time stamp is off since this one is in the future, all saying the same thing:

    RunspaceId          : c4e9d2a7-1b8e-451a-ab00-3eb111b64bbc
    IsFileLink          : False
    Identity            : excallog://xxxxx@xxxxxxxxx.net/?id=RgAAAAAUUlY3o8m0SZqk/w5WsGxMBwDRozwxuz5WQ5I/0YQfbAF6AAA
    LogDate             : 2017-04-12, 4:57:20 PM
    NormalizedSubject   : CAB + Security
    CleanGlobalObjectId : 040000008200E00074C5B7101A82E00800000000F04CCE236DA8D201000000000000000010000000C55BE9526BC6A3408
    IsValid             : True
    ObjectState         : Unchanged

    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, April 12, 2017 5:04 PM
  • that's the exact what I get. however, someone says they can get the following detailed info:

    check the following folder

    <Exchange Installation Path>\v15\Logging\Calendar Repair Assistant\ to see if you can find the log for the user who forwarded the meeting (note: on user's mailbox server if you have multiple ex 16 servers.

    IPM.Appointment item.

    User who performed the action on this instance of the item:

       /o=xxxxxxx/ou=Exchange Administrative Group (xxxxxxxx)/cn=Recipients/cn=xxxxxxxxxxxxxxxxxxxxxxxx

    Apple device flag:


        Recurrence and Exception Info:

        Recurrence Start: 9/1/2015

        Recurrence End: 12/31/4500

        DeletedInstanceCount: 0x00000000 = 0

        ModifiedInstanceCount: 0x00000000 = 0

        ExceptionCount: 0x0000

    Wednesday, April 12, 2017 5:40 PM
  • I see a lot of logs in that directory, but not one for the user who was forwarding the meeting today while out of the office...strange.  Checked all 3 of my servers.  

    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, April 12, 2017 5:47 PM
  • right. it doesn't work for me either.

    The things seems getting worse now. An iPhone user reported today, his Apple map reminded of him this morning 20 minutes before a scheduled meeting to head for the meeting when he was on a bus to office. He accidently opened it and triggered auto forward the meeting request to 200 attendees twice.

    Microsoft claimed if you use Microsoft Outlook client from apple store for CORP account and remove ActiveSync account on apple native client should address the issue. For us it's hard the make such change.

    Friday, April 21, 2017 3:45 PM
  • When reviewing the logs for this issue. Has anyone seen this as a smart forward action from an apple device. I am experiencing a similar issue where users are taking no actions client side or from the mobile device. The affected users are on iOS 10.2 and are active sync enabled. The difference is that my Environment is Exchange 2010 ru14 not Exchange 2016. Has anyone engaged apple or has this been identified as a MS Active sync bug? The last occurrence I had was today, the calendar invite was forwarded out about 20 minutes prior to the event. The forward is sent by an attendee, hits the meeting owner first, and then gets forwarded to everyone else from what I am seeing in the logs. Has anyone seen any of this occur?
    Monday, April 24, 2017 5:01 PM
  • We are having the same problem!! We run Exchange2016 CU4.
    The issue seems to revolve around iPhones, and didn't seem to start until the 10.3.1 iOS update.

    Are people finding this issue when users Snooze the Meeting Reminder from the iPhone?

    Tuesday, April 25, 2017 1:05 PM
  • 10.3.1 doesn't help for us. yes, the issue is triggered once iPhone users Snooze the Meeting Reminder from the iPhone. and currently users have reported they have Apple map on their iPhone, Apple Map with GPS tracking on triggered the event once users open the reminder from Apple map pop up
    Tuesday, April 25, 2017 6:00 PM
  • do you have Apple map with GPS tracking on?
    Tuesday, April 25, 2017 6:02 PM
  • try to disable pop3 and imap features for affected iPhone users to see if this helps. .

    Note: after you disabled pop3 and Imap4, please do power reset on your iPhone. it seems they are not related. However, it has been working fine for us for now. We have tested over the weekend, so far so good:-) Let me know if this works for you.

    Tuesday, April 25, 2017 6:08 PM
  • To all,

    Microsoft has just published the following KB and the issue has been tracked


    Per a Microsoft employee:

    We are seeing an issue internally as well where meeting invites are forwarded by an attendee.  The issue is tracked with this KB article, https://support.microsoft.com/en-us/help/4014990/meeting-invites-are-forwarded-by-an-attendee.  I usually see this issue happen right before the meeting starts.

    From what I understand a workaround is to disable the time to leave feature (TTL) on your device. Settings > Calendar > Default Alert Times > disable Time to Leave.  

    This issue is being worked on by Microsoft and Apple.  Once a fix is available the KB will be updated do document it.  I'll periodically check on it too and post back what I find. 

    Tuesday, April 25, 2017 7:57 PM
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    Tuesday, April 25, 2017 8:11 PM
  • This is exactly what I needed to see!...I was getting some heat from Management for an action plan!

    Is the issue iOS 10.X related?  10.3 related?  10.3.1 related?

    I want to say Thanks to everyone that posts to these Forums.
    Without everyone's input, this issue wouldn't be Public & cause me alot of extra work!!

    I'll prepare an email to our iPhone users with the work around

    Thanks Again!

    Wednesday, April 26, 2017 12:50 PM
  • We have tested Gabriel Bratton's workaround. Once user's iPhone is locked, and user swipe left and choose Snooze on the locked iPhone, it still generate auto forward. If user unlocks his/her phone first, then Snooze it, this won't trigger the auto forward.

    • Edited by exadmin818 Friday, April 28, 2017 4:56 PM c
    Friday, April 28, 2017 4:44 PM
  • I have seen some occurrences were no action is taken at all and seems to be triggered by the reminder itself.
    Tuesday, May 2, 2017 4:51 PM
  • Please note, I am getting this behavior reported from users in Exchange Online as well. The attendee/forwarder is remote mailbox with an iPhone & iWatch. When the iPhone is locked and the user dismisses the reminder on the iWatch, it triggers the meeting forward. This is a hybrid environment with Exchange 2010.
    Monday, May 8, 2017 10:29 PM
  • Can anyone confirm that iOS 10.3.2 beta fixes this issue? Based on my testing it seems to be resolved.

    We tested from the lock screen > swiped > snoozed the meeting popup from an iPad (10.3.2 beta) and iPhone (10.3.1). All settings set to default behavior.

    Thursday, May 11, 2017 3:10 PM
  • I do not have 10.3.2, my iPhone is still on 10.3.1 like you mention, but my phone triggers this all the time.

    What I am confused about is an earlier post indicating a workaround of opening the phone before attending to the reminder.  But on this version of iOS, if I get a notification on the lock screen and then open the phone there is no way to snooze (that I can see/find).  If anyone has any feedback on that, I'm all ears because this is driving folks at work crazy.  


    Thursday, May 11, 2017 5:13 PM
  • I also have an open case with MS and have spoken to their Premier Support who verified, as of yesterday, this issue occurs within the walls of MS.  In order to at least curb this issue on our large meetings I created a transport rule that states if a message's Sender is "insert each user" and The Subject or Body...subject matches these text patterns: "meeting subject", "Accepted: meeting subject", "Tentative: meeting subject", "Declined: meeting subject", "Meeting Forward Notification: meeting subject" - Redirect the message to... a mailboxFill in the meeting subject with whatever your meeting is called, I'd recommend something special like "Daily Check In All Hand Meeting".  That way your search pattern should not capture valid emails.  

    While this is not a fix, it's a Band-Aid for our meetings that generate hundreds of emails a day.

    Friday, May 12, 2017 3:30 PM
  • Hello All ,

    I have also opened a new thread for this kind of issue .Please review it and let me know if there is any update on this issue.

    I will also keep you all posted if we found anything on this case .


    Thanks & Regards S.Nithyanandham

    Tuesday, May 16, 2017 8:26 AM
  • BoldtDH - I have a recurring Wednesday meeting that always triggers these ghost forwards, so I had everyone on the meeting update their iOS yesterday to 10.3.2 and one of the users (who I verified was on 10.3.2) still sent 4 of the forwards this morning in addition to one from a user who did NOT update so unfortunately that did not nip this. We really need Microsoft to get on the ball with this.

    Crystal Chadwick Sr. Exchange Administrator

    Wednesday, May 17, 2017 2:41 PM
  • BoldtDH - I have a recurring Wednesday meeting that always triggers these ghost forwards, so I had everyone on the meeting update their iOS yesterday to 10.3.2 and one of the users (who I verified was on 10.3.2) still sent 4 of the forwards this morning in addition to one from a user who did NOT update so unfortunately that did not nip this. We really need Microsoft to get on the ball with this.

    Crystal Chadwick Sr. Exchange Administrator

    I am confirm we are still experiencing this after 10.3.2 update. Testing showed promise. One user simply swiped to dismiss while locked and has since triggered 10+ emails for today.
    Monday, May 22, 2017 7:48 PM
  • I'm currently also facing this issue. As from what I can read, this has nothing to do with the device itself but it's something Microsoft should fix. Is this information correct?
    Tuesday, May 30, 2017 8:46 AM
  • We had this issue as well, but lucky only one user reported the issue. Deleted the recurring meeting and created new to fix the issue. Also suspect issue is because user edit a recurring meeting on their IPhone that trigger this ghost messages.

    Please mark as helpful if you find my contribution useful or as an answer if it does answer your question. That will encourage me - and others - to take time out to help you. Thank you! Off2work

    Tuesday, May 30, 2017 1:18 PM
  • I tried another fix with one of our IT-only recurring meetings, had everyone turn off their TTL on their iphones/ipads and we were good for 2 weeks.  Unfortunately it happened again today for a user who had theirs off.  Sigh.

    Crystal Chadwick Sr. Exchange Administrator

    Friday, June 2, 2017 5:12 PM
  • I have seen this behavior as well.

    The environment is mostly iOS devices, confirmed that attendees were on the most current iOS. 

    I did confirm that the "rogue" forward requests were definitely originating from the mobile device using MFCMAPI.

    I don't think that snoozing when locked really has anything to do with it.

    I experienced it and i know my phone was locked and i wasn't touching it when a forward went out as i was driving at the time. 

    I reached out to Apple on it and they told me it was a bug in iOS and to do a factory reset of the mobile device to resolve it.

    I was having this happen to me randomly and since doing a factory reset it hasn't happened since. 

    Using Outlook for iOS isn't really a viable workaround, that software is a huge security risk in my opinion since your users are storing valid credentials on an external server out of your control. 

    • Edited by MikeN401 Friday, June 2, 2017 5:26 PM
    Friday, June 2, 2017 5:17 PM
  • It seems that the "Time to leave" notification on iPhone are triggering the resend. After turning this feature off on all IOS deviices the resend stops.


    Sunday, June 4, 2017 6:37 AM
  • I had my users turn off TTL and one of them still sent the forwards last week.  Apple is saying a full wipe is the fix in that case unfortunately.  My user did the full wipe and I'll update if he still sends the forwards after that.

    Crystal Chadwick Sr. Exchange Administrator

    Monday, June 5, 2017 3:24 PM
  • Hi Crystal,

    can confirm same behaviour with 10.3.2 and TTL off, does not seem to be a blanket fix.

    After the wipe, can you confirm if the iOS users did a restore from backup, or just ran the phone from the default install?

    I can confirm switching to Outlook for iOS definitely resolves the issue (but has its own drawbacks, obviously).


    Justin Gillfeather

    Tuesday, June 6, 2017 12:51 AM
  • We did try to create new one and take ownership of the meeting, it still keeps forwarding...
    Wednesday, June 7, 2017 6:43 PM
  • factory reset is not option or solution for this! they have to address the issue either from Apple or Microsoft.
    Wednesday, June 7, 2017 6:47 PM
  • As you have premier support, You should request Microsoft investigate the cause of the issue for you. Actually use transport rule to block subject "FW: meeting-subject" should temporarily stop the forwarding. We only use this for a big meeting with lots of complaints.
    Wednesday, June 7, 2017 6:53 PM
  • Thank you for that post,
    I am working a backlog of issues at my company and had one active and one backlog found so far with this issue.
    Happy to see someone was actually working directly with MS like I used to do when I did server support a few years ago, and gets the skinny from MS directly.
    Thursday, June 8, 2017 6:06 PM
  • Hello All,

    just got confirmation from our Microsoft PPS support engineer today that

    "I have already spoken to my superiors on this and we should have a fix in CU6 , however once we have the CU6 will call you and update".

    Let us have our fingers crossed and see what happens tomorrow, 6/20/17 (expected CU6 release date).

    Monday, June 19, 2017 7:49 PM
  • Thanks for updating this!!!

    Much appreciated!

    Monday, June 19, 2017 8:20 PM
  • We are experiencing very similar EAS issues with recurring meeting appointments and multiple random updates being sent too with an Exchange 2013 CU14 back-end.  I'm looking into details of CU's 15 & 16 now, but wonder if Exchange 2016 CU6 fixes the issue will us slow adopters get some relief or a workaround too?
    Tuesday, June 20, 2017 1:39 PM
  • This also occurs in our environment.  Here is a breakdown:

    Problem:  Recurring meeting updates/invites are being forwarded to original invitees without user interaction. 

    Cause:  Unknown

    Possible Suggested Cause:

    1. Mobile Device (Setting, iOS, etc.)
    2. Setting in Outlook
    3. Setting on the Exchange Server

    Facts in our environment: 

    1. The affected user has their email setup on a mobile device as well as in Outlook 2016 on a PC or laptop
    2. We are unsure if the calendar update/invite is sending from the device or Outlook
    3. The only reports in our environment are from users that have an iOS devices
    4. All iOS devices of users reported with the occurrence have iOS 10+
    5. ‘Time to Leave’ is enabled on the device for Calendar alerts.
    6. The users mail is either On Prem (Exchange 2010) or Off Prem (Ex-Online)

    Troubleshooting Steps Taken:

    1. Made sure each users iOS was the latest
    2. Made sure their default calendar was set to their work email
    3. Tested removing read receipts from the Office Portal of Off Prem users 365 Portal.
    4. Tested disabling the Time to Leave calendar alert option on the iOS device
    5. Tested disabling Time to Leave

    The issue appears fixed, however it just may not be happening to the user again, so it is an assumption.

    This issue has become pressing with no resolution in site.  Please advise if anybody knows of anything.

    Tuesday, June 20, 2017 5:30 PM
  • Is there anyone working a solution? This is a terrible flaw that is affecting us. Today I responded to a text message 19 minutes after my meeting had passed and the meeting notification was forwarded. This is painful!!
    Tuesday, June 27, 2017 3:56 PM
  • Is there anyone working a solution? This is a terrible flaw that is affecting us. Today I responded to a text message 19 minutes after my meeting had passed and the meeting notification was forwarded. This is painful!!
    We are getting this on exchange online too 
    Tuesday, June 27, 2017 3:58 PM
  • Any update on a possible resolution? I was hoping maybe someone else had an update for an existing case before I reach out and get the runaround that I'm pretty sure I'll get from Microsoft.
    Tuesday, June 27, 2017 4:52 PM
  • CU6 was released yesterday but I did not see any information about this issue getting fixed.

    Could you please confirmed if this issue was addressed on CU6 released?

    Wednesday, June 28, 2017 10:22 AM
  • Yes, we are testing in our Lab now. I will post the testing results once this is done.
    Wednesday, June 28, 2017 1:06 PM
  • I have observed same problem with outlook client on my PC. So far it is auto forwarding one of our recurring meeting invite almost everyday random times. Sometimes 4-5 times in a day. Not sure how it is happening. Verified that there are no rules set up as such.
    Wednesday, June 28, 2017 2:17 PM
  • Upgraded our lab to CU6 already. However, CU6 has not addressed the calendar auto forwarding issue yet. Microsoft has escalated our case now... Hopefully Apple's next release iOS will address the issue. Does anyone have any updates from Apple?
    Thursday, June 29, 2017 2:33 PM
  • Did your account forward the meeting? do you have Apple iOS devices, iPhone, iPad or iWatch configured to sync with your corp email?
    Thursday, June 29, 2017 2:36 PM
  • Hello All , 

    We are also facing the same issue in our environment and we had opened a case with apple and we got an confirmation from Apple saying that it was addressed in IOS release (10.3.3 ) :)

    Thanks & Regards S.Nithyanandham

    Thursday, June 29, 2017 2:47 PM
  • Thank you for update. Have you or anyone tried the latest iOS 10.3.3 beta 5 yet? Does anyone have updates on iOS 10.3.3 beta test on the issue?
    Thursday, June 29, 2017 3:08 PM
  • Hello exadmin818 , 

    Not yet we have tested with IOS 10.3.3 beta , once it is done i will share you the results .

    Thanks & Regards S.Nithyanandham

    Thursday, June 29, 2017 3:26 PM
  • All,

    We have downloaded iOS 10.3.3 beta 5 that Apple released late June, we have tested in our lab with Exchange 2016 CU6, it seems iOS 10.3.3 does fix the issue. We will continue to test in production (CU2) and iOS 10.3.3 beta 5. if everything is working fine, we will test it on iOS 11 beta 2 as well.

    Monday, July 3, 2017 1:16 PM
  • Perfect, we have the same issue in our workplace however not on the scale some users are reporting. We are running an Office 365 environment, a recent move from Exchange 2016 CU4. Just to confirm with your test environment, you are having to put all iOS devices on 10.3.3 beta 5? 

    Just wondering if the issue got progressively worse as with no release date on 10.3.3 as of yet (although likely this month) is it worth us moving those currently effected onto the beta?

    Thanks all for the previous troubleshooting. 

    Tuesday, July 4, 2017 9:39 AM
  • In our test environment, we have one 10.3.2 and one 10.3.3 beta 5. We are able to duplicate the issue on 10.3.2 device, however, so far no forwarding is generated on 10.3.3 beta 5 users. We are still testing.
    Wednesday, July 5, 2017 7:08 PM
  • Any updates on your testing, or since iOS 10.3.3 beta 6 is out?


    Monday, July 10, 2017 5:10 PM
  • This happened to my team when I snoozed a meeting.  One thing we noticed is that this occurs on recurring meetings that existed prior to our migration to MS Exchange 2016.  This does not occur on new recurring meetings.  We did a double hop migration from Exchange 2007 to 2013, then to 2016.
    Tuesday, July 18, 2017 4:07 PM
  • Finally Apple has released 10.3.3 today. Please go ahead and test it. it works with Beta 5 and Beta 6. only issue with beta is sometimes, it didn't pop up scheduled event at all. it seems the final release has fixed the bug.


    Wednesday, July 19, 2017 6:37 PM
  • According to our extensive tests, it appears the issue has been fixed by iOS 10.3.3 though there is no release note mentioned the fix. Good job Apple. Microsoft PPS misled us on the issue as they told us the fix should be Exchange 2016 CU6. CU6 didn't address the issue.

    • Marked as answer by exadmin818 Monday, July 24, 2017 1:46 PM
    • Edited by exadmin818 Monday, July 24, 2017 1:54 PM
    Monday, July 24, 2017 1:46 PM
  • I just sent out an email to all our iPhone users, advising them to update their phones.  I hope this fix's the issue. 
    Monday, July 24, 2017 2:24 PM
  • The "fix" must require Exchange 2016 CU6 + iOS 10.3.3, because we are still seeing the issue occur from 10.3.3 devices. However, we have not upgraded to CU6 yet. Has anyone else seen the same?
    Tuesday, August 1, 2017 1:50 PM
  • Meanwhile... the rest of us running Exchange 2013 are holding our breath waiting for a resolution :/

    Thursday, August 3, 2017 3:46 PM
  • Just thought I'd jump in on this:

    Today there was a reoccurring calendar invite sent out to several parties - it was sent "On Behalf" of another person. Both individuals claimed they didn't send anything.

    During my investigation, I went to both individuals in Exchange Console and looked to see if there even any rules that allowed them to "send on behalf", and there were none.

    I searched the web and found this post (thankfully) and saw that things were address in IOS 10.3.3 - both parties have I-Phones but are already at 10.3.3. What bothers me however, is how could any device 'Send of Behaf' when there are no such rules assigned in Exchange? That makes me wonder if the problem is not IOS and resides in Exchange.

    I am running Exchange 2010 SP3

    Looking at Windows Update on the server, there are two that are new that I haven't installed yet: (KB4034670) and (KB4035036) - not sure if they will fix anything but thought I'd mention that they have not been installed yet..

    Now, further investigation: I noticed in Message Tracking, that the very first event was sent by source: storedriver which by definition is "The event source was a MAPI submission from a mailbox on the local server".

    Does that also point at Exchange and not IOS?

    Thursday, August 17, 2017 1:36 PM
  • One week later, at the same time, another reoccurring e-mail was sent 'on behalf of' the person who created the original event.

    Looking deeper, I still couldn't find any rules, or even an option to automatically forward events on a reoccurring date and time within Outlook 2010, so I turned again to IOS.

    Looking at the calendar item on the sender, I noticed something - a 'second alert' setting. I have never seen a second alert setting anywhere before, so changed it from "Time to Leave" to off, but then I noticed that it didn't make that change for all the future reoccurring events *sigh*.

    So I shifted my attention to the person who originally created the event and look at his calendar in IOS - there was no second alert setting at all! So I looked at some of my own reoccurring calendar items on my IOS device, and none of them even had an option for a second alert.

    So no I am scratching my head - how does a second alert even get set? I don't see anything like that in Outlook, nor do I see a setting for that in IOS. ???

    As much as I wanted to see if turning off the second alert, the meeting originator didn't share in my enthusiasm and wiped out the event and created a new one. With that said, I will probably never know the root cause of this.

    For those of you plagued with this issue, does the person who is automatically sending these reoccurring events have a second alert option set on their IOS calendar?

    • Edited by Dorpond Thursday, August 24, 2017 1:10 PM
    Thursday, August 24, 2017 1:06 PM
  • Disable time to leave feature in iPhone   (Go to Settings\Calendar\Default Alert Times)

    (You may also check if the user adding himself/ herself as a participant (or using a DL where he/ she is a member) in the meeting that he had issue with. Ask the user to expand the group and remove him from the participant list.)

    Thursday, August 24, 2017 8:09 PM
  • OK thanks for that.

    After reading your comment, I searched the web and indeed found this, which has a couple links within that explains more in detail:


    Thanks Nishanth

    Friday, August 25, 2017 2:58 PM