How to keep OST files in Veeam Agent backup

You can edit or delete subkeys of the FilesNotToSnapshot registry key to include automatically excluded files in the backup. For example, to include OST files, do the following:

1. Open Registry Editor (click the Start button, select Run, enter regedit in the Open: box and select OK).
2. Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\BackupRestore\FilesNotToSnapshot registry key.
3. Delete the OutlookOST value.

Keep in mind that the OST files exclusion is recommended by Microsoft. To learn more about the recommendation, see this Microsoft Tech Community article.