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XLSX attachment file being removed for office 365 mailbox RRS feed

  • Question

  • Hello Everyone,

    We are in hybrid environment exchange 2016 hybrid.

    Edge transport server is also exists.

    Few email alert being triggered from our in house application server with .XLSX attachment (report) and it will distribute the emails to few email addresses.

    Exchange online users reporting that when they receive the email the attachment automatically changed as .txt.

    txt file contains "This attachment was removed".

    how to fix this issue.

    Onperm users able to receive the attachment without any issues.



    Thanks, Venkatesh. "Hardwork Never Fails"

    Tuesday, November 26, 2019 4:24 PM

All replies

  • Hi imvenkat,

    It seems like a behavior by Exchange Online Malware Filters. Go to Exchange Online Admin Center > Protection > Malware Filter, and check the policies there. Under their settings, check Common Attachment Types Filter list to see if the corresponding extension (which is .xlsx in this case as you mentioned) is listed there. If so, which I highly suspect it is, remove that file type from that list to prevent it from being blocked.

    https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/configure-anti-malware-policies

    Regards,
    Burak V.

    Tuesday, November 26, 2019 6:47 PM
  • in our org. it is completed disabled.

    Thanks, Venkatesh. "Hardwork Never Fails"

    Wednesday, November 27, 2019 2:22 AM
  • Hi imvenkat,

    I want to confirm with you: Do this phenomenon occurs when you send emails to Exchange on-premises?

    Does there exist any third-party email filter exist in your organization?

    Regards,

    Kyle Xu


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

    Friday, November 29, 2019 1:02 PM
    Moderator
  • Hi imvenkat,

    Any update about this thread now?

    Regards,

    Kyle Xu


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

    Tuesday, December 3, 2019 8:21 AM
    Moderator
  • Hi Kyle,

    Yes we are using CISCO ironport as email gateway/Relay server.

    Application will use our ironport ip as relay server (SMTP server).

    Email will be generated by application from Generic email address.


    Thanks, Venkatesh. "Hardwork Never Fails"

    Tuesday, December 3, 2019 3:04 PM
  • Any update please ?

    Thanks, Venkatesh. "Hardwork Never Fails"

    Friday, December 6, 2019 6:45 AM
  • Hi,

    In this situation, I would suggest you try to bypass CISCO ironport temporarily. This phenomenon may be caused by it. For Exchange online, it will block this attachment directly rather than change it to .txt file.

    Regards,

    Kyle Xu


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

    Friday, December 6, 2019 1:15 PM
    Moderator