Note: if you have a fast internet connection and your .OST file is corrupted, the best course of action would be to re-create the profile so that a new .OST file is created, as using the Inbox Repair Tool would be more time-consuming.
Alternatively, you may also try to delete .OST file without profile recreation. 

You can use the Inbox Repair Tool (scanpst.exe) to repair corrupted Personal Folders (.pst) and Outlook Data (.ost) files. This is useful when your OST file is relatively big (more than 5 GB) and it would take a long time to recreate it. Also it can be useful when you are getting errors when importing data from a PST file.

Important: you may need to run the scanpst.exe file several times (5-8). Keep doing this until it says that no errors were found in the file.

To run the Inbox Repair Tool, follow these steps:

  1. Make sure Outlook is closed.
  2. Make sure that the Show hidden files and folders option is enabled in your Folder options. The file scanpst.exe is a hidden file, so you need this setting to be enabled to locate it.
    To check this setting, follow these steps:
    1. Click Start, then Control panel.
    2. Click Folder options or File Explorer Options, then switch to the View tab
    3. Under Hidden files and folders, make sure the Show hidden files and folders option is selected, and then click Ok.
      hidden files
  3. Browse to the location of your Microsoft Office installation:
  4. If you cannot find the scanpst.exe file using Search, try to locate the file manually. Check the following locations for the file (location depends on which version of Windows you are using):
    • 64-bit Windows Vista, Windows 7, Windows 8 and Windows 10
      • drive:\Program Files\Microsoft Office\OFFICE16
      • drive:\Program Files\Microsoft Office\OFFICE15
      • drive:\Program Files\Microsoft Office\OFFICE14
      • drive:\Program Files\Microsoft Office\OFFICE12
    • 32-bit Windows Vista, Windows 7, Windows 8 and Windows 10
      • drive:\Program Files (x86)\Microsoft Office\Office16
      • drive:\Program Files (x86)\Microsoft Office\Office15
      • drive:\Program Files (x86)\Microsoft Office\Office14
      • drive:\Program Files (x86)\Microsoft Office\Office12

Note: if scanpst.exe file still cannot be located, try to repair Office programs.

  1. Double-click the scanpst.exe file to open the program.
  2. Click Browse to locate the corrupted .pst/.ost file
    By default the .pst/.ost files can be located in the following folders:
  • drive:\Users\<username>\AppData\Local\Microsoft\Outlook
  • drive:\Users\<username>\Roaming\Local\Microsoft\Outlook
  • drive:\Users\<username>\Documents\Outlook Files
  • drive:\Users\<username>\My Documents\Outlook Files
  • drive:\Documents and Settings\<username>\Local Settings\Application Data\Microsoft\Outlook
  1. Click Start. The Inbox Repair Tool scans the file and reports whether it found any errors. Click Repair if any errors were found.
  2. Click OK.