If the original Microsoft Exchange profile was not modified, you can still start the Microsoft Exchange client offline with the old OST and recover the data by moving the messages from the OST to a PST file. However, if the old profile was deleted or modified (by using it to log onto a different mailbox) then the data in the OST is lost.
This is because security on an OST works so that Windows NT authentication cannot be used when you work offline. Therefore, you must "prove" that you're allowed to log onto the server-based master before the OST file gives you local access. To do this, Exchange Server creates an encrypted "cookie" from your mailbox's unique entry ID while you are successfully logged into the Exchange Server computer. This cookie is securely stored in your Exchange Server profile. Essentially, your profile stores this key for the OST. Every time you try to access the OST file it checks your profile for the existence of this key.
If you modify the profile or try to connect to a new mailbox or new server with the current profile, Microsoft Exchange replaces this key with a new value from the mailbox that was created. At this point, you cannot access the data that was contained in the OST created against the first mailbox.
Steps to RecoverIf you have not modified your profile or attempted to log on to the new mailbox, use the following steps to copy the offline messages to a PST:
- Start the Exchange Client OFFLINE.
- On the Tools menu, click Services.
- Click Add.
- Add a Personal Folders (PST) service.
- Select the messages that you want to copy.
- On the File menu, click Copy.
- In the Copy to dialog box, select the personal folders (PST) that you created in step 4.
- Click OK.
- Repeat steps 5 through 8 for each folder that contains messages.
NOTE: offline folders (OSTs) should not be considered as backups of your server based store. For more information on proper server backups, refer to the Microsoft Exchange Server Administrator's Guide, Chapter 15.
Article ID: 163589 - Last Review: May 31, 2009 - Revision: 1