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?

Moving an ost-file to another location is indeed a bit more trickier than moving an 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 2010 and previous

  1. Close Outlook.
  2. Copy the ost-file to the location where you want it to go.
    The defaults location for the ost-file is;
    • Windows Vista, Windows 7, Windows 8 and Windows 10
      C:\Users\%username%\AppData\Local\Microsoft\Outlook
    • Windows XP
      C:\Documents and Settings\%username%\Local Settings\Application Data\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 choose 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 for Outlook 2013 or Outlook 2016 Exchange, IMAP and EAS accounts

Moving the ost-file in Outlook 2013 and Outlook 2016 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 an IMAP pst-file or Hotmail ost-file

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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