Move the ost-file to another disk or folder location

I’m running out of disk space on my main drive and noticed that my ost-file was really big. I know how to move pst-files, but that method does not seem to apply to ost-files.

How can I move my ost-file to another location?

Move OST-File buttonMoving an ost-file to another location is indeed a bit more trickier than moving a pst-file.

While it is recommended to leave the ost-file in its default location, there are still valid reasons for moving it to another location like for instance when using a smaller Solid-state Drive (SSD) as your main disk.

Move the ost-file for an Exchange account in Outlook 2007 and Outlook 2010

Exchange Account buttonMoving the ost-file to another location in Outlook 2007 and Outlook 2010 takes a bit of clicking but is still an easy process with the following step-by-step instructions.

  1. Close Outlook.
  2. Copy the ost-file to the location where you want it to go.
    The default location for the ost-file is;
    • C:\Users\%username%\AppData\Local\Microsoft\Outlook
  3. Use the Mail applet in Control Panel to open your E-mail Account settings.
  4. Double click on the Exchange server account and click on the button: More Settings…
  5. Select the Advanced tab.
  6. Disable the option: Use Cached Exchange Mode.
  7. Press Apply.
  8. Press the button: Offline Folders File Settings…
  9. Press the button: Disable Offline Use
  10. Press OK on the warning dialog that pops-up.
  11. Press again on the button: Offline Folders File Settings…
  12. Now browse to the new location of the ost-file.
  13. Press OK to return to the Advanced tab.
  14. Enable the option again for Use Cached Exchange Mode.
  15. Close all open dialogs and rename the ost-file in the old location from .ost to .old
  16. Start Outlook.

Outlook will now use the ost-file from the new location and you can safely delete the ost-file from your main disk.

Offline Folder File Settings
It takes some clicking to make the ost-file location field editable.

Move the ost-file for Outlook 2013 / 2016 / 2019 / 365 Exchange and IMAP accounts

Outlook buttonMoving the ost-file in Outlook 2013 and later is no longer possible via the interface in Outlook itself. Instead, the quickest way to go would be to create Symbolic Links instead.

With a Symbolic Link, you’d be creating a “pseudo file” which is only a pointer to the actual file. This differs from a shortcut as a shortcut is actually an lnk-file whereas a Symbolic Link will retain the original file name.

This may sound all very complex, but the actual process is quite easy and very effective. You’ll find step-by-step instructions in the guide: Moving the ost-file of an Exchange, Outlook.com or IMAP account.

The guide mentioned above, also contains 2 other methods to moving the ost-file’s location which doesn’t involve creating Symbolic Links but do require you to recreate the account.

Note: Don’t place the ost-file on a network share. This is unsupported and it would defeat the purpose of enabling Cached Exchange Mode. The ost-file should reside on an internal drive.

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