Mailbox Size in Outlook different to size on Server

I have a user who's mailbox size in Exchange 2003 System Manager is showing as over 2GB and at the limit, but when I got to their Outlook -> Mailbox Cleanup and look a the total Size (including Calendars, Contacts etc) as only 586MB.

Can someone explain by the mailbox on the server is so much larger and what I can do to reduce it?

Thank you
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colin_PaulConnect With a Mentor Commented:
Hello EICT,

Please check first :-
Is Outlook in cached mode?  Then you're looking at the local cache and not the server and you have a synchronization issue.  Turn off cached mode and see if it shows up.  If so, you might want to delete the OST file and, if you want, re-establish cached mode.

To resolve this issue:-

Uncheck Cached Exchange Mode, close Outlook, reopen Outlook, identify the offending items, delete the items, re-check Cached Exchange Mode, close Outlook, reopen Outlook.

Resources -


Colin Paul
AmitConnect With a Mentor IT ArchitectCommented:
Does this user have any handheld device like blackberry. do one thing use PFDAVAdmin and extract the report for this user. Use this

Once you have report you can then find out where data is consumed. Also Outlook is not a good way to check mailbox size. It is design to access mailbox from server. So, don't think outlook will tell you exact size. It is server where data resides and if it is showing 2GB on server that means 2 GB is used. Where? That you need to find using the tool, i have given.
If you just clean up the user OST file you might encounter some differences between the server size and the file because of the retention time on the server.

The server will not completely erase everything as you did on the client side.

To reflect the size more accurately you have to roads, reduce your retention time per server or database.  export user's emails to a pst file, assign a new mailbox to the user and import the pst file.  After few minutes from the import your server should reflect about the same amount like the user.
andrea vitielloCommented:
Thanks colin_Paul,

your solution does work!

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