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Using IMAPv4rev1 with Outlook 2003 - PST File Size

the_griz asked
Last Modified: 2013-12-06
I have a Red Hat server running IMAP4rev1.  I am migrating several Outlook 2003 POP3 accounts to use IMAP.  However I was dismayed to find that Outlook's IMAP still requires a local PST file.  Furthermore, it appears this file must be a 97-2002v of the pst file which has a limit of 2GB,  

Is there a way to configure Outlook 2003 to work with IMAPv4rev1 and create a local PST that is 2003v which can exceed 2GB?

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Graham N.Group MD

Outlook 2003 does not have a 2GB limit on PST file!

In fact I think the limit was dropped in Office (2001) XP upwards -for sure older versions of Outlook had a 2GB limit on PST files - but a correctly patched (Office 2003 SP2) version of Office 2003 can handle PST files well over 20GB (yes I have one user who insists on keeping every piece of email they ever had).

As for using Outlook with any version of IMAP - the local PST files are syncronized with the server side IMAP folders based on the settings you defined within Outlook itself - either "headers only" or "full message".

If you are experiencing problems with moving the POP3 messages to IMAP ensure that the server side IMAP folders are MBOX compliant - otherwise Outlook will take forever and a day to sync/move messages around.

We have Outlook working successfully with IMAP4 on both Linux and Windows boxes with no problems whatsover - including large mailbox/folder sizes well over 2GB.


While I agree that Outlook 2003/7 use PST files capable of more than 2GB, it appears these programs will not create a such PST file when connecting to an IMAP4rev1 server.
For example:
When Iconnect to an IMAP4rev1 account with Outlook 2003 (or even Outlook 2007), this creates a PST file that is a "Personal Folders File (97-2002)" (under properties).  Therefore, the 2GB limit is true.  

Follow-up Question: Is there a way to force Outlook 2003 to create "2003 PST file" that is capable of >2GB AND work with IMAP4rev1?

SIDE Note:  The 2GB limit may not really be in play too much anyways.  In my moving files from the local disk to the IMAP account on the server, Outlook cached the full emails in the new PST.  Thus I hit the 2GB limit.  But if I simply delete the IMAP account in Outlook and readd it, only the headers get downloaded and the full mesages are not cached.  Therefore, I am now working with an IMAP folder in excess of 3GB but only using 175M on the local PST file, as it is just working with headers....

Please let me know if there is an answer to my follow-up question.
Graham N.Group MD

Sorry, but where are you finding the "Personal Folders File (97-2002)" category - the PST files created in the Document & Settings folders of all of our users are all standard 2003 variety PST files (Office Outlook Personal Folders File)- I just created a new IMAP4 account on Office 2007 to check this is also the case for 2007.

The PST file created by Outlook will default to the same format as any pre-existing Personal Folders - if your users have imported or are using PST from older versions that may have reset the default - or maybe if you have deleted the default Personal Folder this would affect how Outlook adds new folders.

However, as I say, the users at our client's site are definately on 2003 style PST files - and the test accounts I just created here are also on standard 2003 PST format.

Group MD
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I accepted the last comment, but I still feel this is not the complete story.  According to that link, Outlook 2003/7 will create a 2GB-bound pst file which seems to be different than what you are experiencing with your users.  It is in fact what all of my Outlook 2003 have - IMAPv4rev1 which you find under File->Data Management-> Select PST and click Settings.  The PST type is a "Personal Folders File (97-2002)".

Now, you can get around the 2GB limit by removing the IMAP account from within Outlook and then adding it back in.  The PST file will be recreated and will only hold headers of messages until you ddownload and read.  As long as you watch your file size limits, it will be an effective way for Outlook to interact with an IMAP structure larger than 2GB.  If you open enough mail to reach the 2GB PST limit, remove the IMAP account within Outlook again and re-add.  This is not an elegant approach, but I believe it will work for quite a while at least for my users.

Graham N.Group MD

Hi the_griz:

I rechecked the PST files at one of my clients sites this afternoon - and sure enough the PST files are all the "Office Outlook Personal Folders File" variety. During a quick check I found 4 that were over 2GB (I didn't check all users as there are over users at this particular location) and one case their PST file is just over 9GB.

The only thing that is different about this set-up and what you are expereincing is that you are trying to create a PST file from an existing "over 2GB" IMAP account.

This is what led me to find the Microsoft page earlier today. I was attempting to recover some lost email messages from an MBX (IMAP4) file today for one of my clients using Outlook Express (quick and dirty solution I know but normally in tech support all the user cares about is how fast you achieve something).

The mail archive for this account was just over 2GB and no matter what I did I could not access it with Outlook Express - I then tried Outlook and got the same result. So just to see if the problem was size related - I split the MBX (IMAP) file in half - then tried again with Outlook - and this time it worked no problem.

After recovering the mails for my client - I decided to test the theory a bit more - and leaving the file split - I set an account in Outlook and checked it with the split file - no problems.  I started appending messages on to that account until just over the 2GB limit - and bang Outlook failed to connect.

I reapeated the above test creating a secondery account linked to IMAP on another Outlook - went through the split test ok and then added messages to over the 2GB limit and still no problem.

So the bottom line seems to be:
1)  if the IMAP file (account) is already bigger than 2GB then Outlook can not open in the first place.
2) if IMAP account is set up as the only account then Outlook will only handle 2GB
3) if IMAP folder is secondery account and initial IMAP folder is smaller than 2GB - Outlook handles it correctly.

Hope all this helps.

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