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Why do the PST files of IMAP account type grow in size? RRS feed

  • Question

  • I have a GMail account set to IMAP type on Outlook 2010.

    I understand that IMAP doesn't download email messages, but synchronizes messages for view at the time of Outlook while opened.  All the messages are supposed to be stored in the server only.

    I understand the Outlook.pst might have information of the calendar and tasks.  What about the emailAddress.pst files?

    Friday, March 3, 2017 12:14 AM

Answers

  • I think we are getting somewhere here.

    I do view folders in the mail server other than the Inbox.  All the time I had supposed they would not be downloaded until I read them and the local copy is temporary and automatically deleted upon exit.

    To repeat, the OST data file is a MIRROR of what is contained pn the server so that you can work on your items when "offline" (not connected to the server(. All the folders in your account that you have "subscribed" to will be sync'd when Outlook connects. Nothing gets deleted from an IMAP folder unless you specifically delete those items yourself. If it automatically deleted those folders "upon exit" - there would be nothing left on the server OR if it just deleted items in the .OST file, would mean that it would download the same info over and over and over again each time you connected to the account which would make absolutely make no sense.

    To view "subscribed" folders,

    - right-click the root of your IMAP account
    - select "IMAP Folders"
    - select the "Subscribed" tab
    - shows the list of the folders you are "subscribed to"

    (if you haven't "subscribed" to a folder, nothing done on the server will be reflected in the folder in OUtlook and vice-versa).

    This is how IMAP accounts work using ANY email client - nothing specific to do with Outlook.

    Understanding Email Protocols (POP, Imap, MAPI, EAS, Exchange)
    http://www.contactgenie.info/understanding-email-protocols-pop-imap-mapi-eas-exchange


    Karl Timmermans [Outlook MVP] "Outlook Contact Import/Export/Data Mgmt" http://www.contactgenie.com

    • Marked as answer by healee Friday, March 10, 2017 1:54 AM
    Wednesday, March 8, 2017 10:59 PM

All replies

  • Hi,

    Up until Outlook 2007, by default an IMAP account will indeed be set to “Download headers only”. However, with Outlook 2010, this default has changed to “Download complete item including attachments”. So first have a check and see if it was configured to "Download complete item including attachments".

    You can change these default settings in your Send/Receive settings:

    File-> section Options-> section Advanced-> button Send/Receive…-> Edit…

    Regards,

    Ethan Hua


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

    Friday, March 3, 2017 8:46 AM
  • However, I deleted everything in the inbox every time after reading.  So where does the bulk of the PST file come from?
    Saturday, March 4, 2017 7:16 AM
  • However, I deleted everything in the inbox every time after reading.  So where does the bulk of the PST file come from?

    There is a big difference between "deleting" items and recovering the space originally used by those items.

    How to Compact the Data File When you Close Outlook
    https://www.slipstick.com/outlook/config/how-to-compact-the-data-file-when-you-close-outlook/


    Karl Timmermans [Outlook MVP] "Outlook Contact Import/Export/Data Mgmt" http://www.contactgenie.com

    Monday, March 6, 2017 1:52 AM
  • Karl is right, you can do so as well, you can remove Outlook Duplicate itmes to reduce the file size of Outlook data file.
    Tuesday, March 7, 2017 6:04 PM
  • The inbox is empty and I have just compacted the file before I took the screenshot below.  It is not the Outlook.pst file I am talking about.  I presume Outlook.pst file has tasks, calendar and contacts as well.

    Please see below.  The file in question is a gmail account and the small file is a yahoo account.  How to explain that?  The gmail file was more than 1 gig big before compaction.  If the inbox is empty duplicate email messages shouldn't be an issue.  Anyway I am not too sure how to remove duplicated messages if there is any.

    Wednesday, March 8, 2017 4:49 AM
  • I don't quite follow your instructions from here.  What could the free PST Management Tool do?

    By the way, I have said my inbox is emptied every time.  I usually transfer those messages I want to  Outlook.pst for keeps and delete the rest.  And I believe all other messages not come to the inbox would stay at GMail server.

    Wednesday, March 8, 2017 6:33 AM
  • I don't quite follow your instructions from here.  What could the free PST Management Tool do?


    Quite frankly I don't quite follow where this thread is going.

    #1 - What exactly is your question/concern? You compacted the file and it got reduced in size. As for difference in size between 2 different email accounts - how can anyone answer that without knowing the volume of emails for each given account? Something is simply not making any sense. (BTW - an empty PST file would be around 256K)

    #2 - Like you, am also at a complete loss to understand the reference to "duplicate items" especially if you've deleted everything from your primary folder(s) (i.e. <Inbox>). BTW, did you also empty the contents of the <Deleted Items> folder to maximize space recovery?

    Going back to your original post - the IMAP PST file is a <local> mirror of what is contained on the server (as described by <Ethan Hua> - the data gets sync'd everytime Outlook connects to the account.

    So to start this over, what exactly is the question/issue/concern/problem?


    Karl Timmermans [Outlook MVP] "Outlook Contact Import/Export/Data Mgmt" http://www.contactgenie.com

    Wednesday, March 8, 2017 6:49 AM
  • The question I ask is why the PST file keeps growing even after I empty the Inbox and the Deleted Items folder every time after I read the messages.  At this stage I even compact the file every time after I empty them.  I am not asking the difference between the two PST file I had highlighted.  The smaller GST file which is Yahoo mail just happens to be there though it is also growing, but not as fast or not as much as the GMail one.

    How can a file be more than 600M big while there is no email message?  While there is no message, definitely there will be no duplicate message.  What I am not too sure and expect some of your experts could tell me is whether what are on the GMail server is also reflected on the PST file though they are not downloaded to the local computer.

    Wednesday, March 8, 2017 9:22 AM
  •  What I am not too sure and expect some of your experts could tell me is whether what are on the GMail server is also reflected on the PST file though they are not downloaded to the local computer.

    Still not at all clear about your scenario but just to be very clear - IMAP will sync every folder that you have "subscribed" to so it's not only the <Inbox>. What exactly are you referring to in terms of "items stored at the server level" that are not being downloaded to the local computer?

    A little puzzled with this since it's not complicated to determine. Specifically, what do you see in your GMail account using Webmail (your browser) that you don't see using Outlook? Also, if this is in reference to "email folders" (other than <Inbox> - how exactly did those email items get into those folders since that would had to be done manually - either at the server level or via Outlook (desktop).


    Karl Timmermans [Outlook MVP] "Outlook Contact Import/Export/Data Mgmt" http://www.contactgenie.com

    Wednesday, March 8, 2017 6:10 PM
  • I think we are getting somewhere here.

    I do view folders in the mail server other than the Inbox.  All the time I had supposed they would not be downloaded until I read them and the local copy is temporary and automatically deleted upon exit.

    Wednesday, March 8, 2017 10:10 PM
  • I think we are getting somewhere here.

    I do view folders in the mail server other than the Inbox.  All the time I had supposed they would not be downloaded until I read them and the local copy is temporary and automatically deleted upon exit.

    To repeat, the OST data file is a MIRROR of what is contained pn the server so that you can work on your items when "offline" (not connected to the server(. All the folders in your account that you have "subscribed" to will be sync'd when Outlook connects. Nothing gets deleted from an IMAP folder unless you specifically delete those items yourself. If it automatically deleted those folders "upon exit" - there would be nothing left on the server OR if it just deleted items in the .OST file, would mean that it would download the same info over and over and over again each time you connected to the account which would make absolutely make no sense.

    To view "subscribed" folders,

    - right-click the root of your IMAP account
    - select "IMAP Folders"
    - select the "Subscribed" tab
    - shows the list of the folders you are "subscribed to"

    (if you haven't "subscribed" to a folder, nothing done on the server will be reflected in the folder in OUtlook and vice-versa).

    This is how IMAP accounts work using ANY email client - nothing specific to do with Outlook.

    Understanding Email Protocols (POP, Imap, MAPI, EAS, Exchange)
    http://www.contactgenie.info/understanding-email-protocols-pop-imap-mapi-eas-exchange


    Karl Timmermans [Outlook MVP] "Outlook Contact Import/Export/Data Mgmt" http://www.contactgenie.com

    • Marked as answer by healee Friday, March 10, 2017 1:54 AM
    Wednesday, March 8, 2017 10:59 PM