How to Reset .ost Files

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If users are not able to preserve their current .ost files with Microsoft® Outlook® 2003, perhaps because you cannot restore the original database, they will need to reset their .ost files. For more information, see Recovering a Mailbox Database Using a Dial Tone Database in Exchange Server 2003.

Procedure

To reset .ost files

  1. Start Outlook in Offline mode, and salvage desired items to an Outlook data file (.pst file).

  2. Start Outlook again, and select Connect to go online with the new Exchange database.

  3. On the Tools menu, click E-mail Accounts.

  4. Click View or change existing e-mail accounts, and then click Next.

  5. Click the Microsoft Exchange Server account, and then click Change.

  6. Click More Settings, and then click Advanced.

  7. Clear the Use Cached Exchange Mode check box, and then click Apply.

    Important

    You must click Apply in order to complete the next step. After you click Apply, this message appears: "You must restart Outlook for these changes to take effect." Do not exit Outlook at this point.

  8. Click Offline Folder File Settings, and then click Disable Offline Use. A prompt appears: "Exchange is currently in recovery mode. If you make changes to your Offline Folder Files settings, your existing .ost file will be removed from your profile and you will not be able to use the file. Do you want to continue?" Click Yes. Click OK, Next, and Finish until you have exited the E-mail Accounts wizard.

  9. Close Outlook.

    Important

    You must exit and restart Outlook before continuing with the next step.

  10. Start Outlook again, and then click Connect to go online with the new Exchange database.

  11. On the Tools menu, click E-mail Accounts.

  12. Click View or change existing e-mail accounts, and then click Next.

  13. Click the Microsoft Exchange Server account, and then click Change.

  14. Click More Settings, and then click Advanced.

  15. Select the Use Cached Exchange Mode check box.

  16. Click Offline Folder File Settings, and then change the name of the .ost file.

    For example, if the file name is outlook.ost, name it outlook1.ost. You can also change the file path if you want to.

  17. Click OK, and a prompt appears: "The file filename could not be found. Would you like to create it?" Click Yes, and then click OK, Next, and Finish to exit the E-mail Accounts wizard.

  18. Exit, and then restart Outlook.