How to Fix Outlook Start-up Errors in Windows

Windows • Ryder Cragie • 5th September 2022

Notices and Disclaimers

  • The fixes I have provided are not guaranteed to work successfully. The configuration or any limitations of your computer, network, or remote server could have an effect.

  • I am not responsible or liable for any data loss that may occur. Follow these steps at your own risk. You shouldn't lose any data as long as your emails can be pulled back down from the cloud correctly, which is usually the case.


If Outlook doesn’t open and you see an error, the data file may have been corrupted. This article will explain how to fix it.

What are Outlook Data Files?

Outlook data files store the contents of your emails, headers, metadata, and the mailbox structure. They have file extensions of ".pst", ".nst" and ".ost". Sometimes these files become damaged or corrupted resulting in the Outlook application either running slowly or not running at all. The data files may need to be repaired or recreated.

Run System Scans and Repairs

  1. Close the Outlook application.

  2. Open Run (Windows Key + R).

  3. Type "cmd".

  4. Press Ctrl + Shift + Enter in the Run box to open Command Prompt as an administrator.

  5. If prompted to enter your Windows administrator password, please do so.

  6. Type "dism /online /cleanup-image /restorehealth" and press enter to run an online repair.

  7. Type "sfc /scannow" and press enter to run a local System File Check (SFC).

  8. Type "chkdsk" and press enter to run a disk check.

  9. Repair/reinstall Office in Control Panel\Programs\Programs and Features.

  10. Reboot your PC.

Repair Original Data Files

If running system scans and repairs didn't help, you can try repairing the Outlook data files.

  1. Close the Outlook application and browse to one of the following file locations, dependent on the version of Office you have installed:

  • Outlook 2019: C:\Program Files (x86)\Microsoft Office\root\Office16

  • Outlook 2016: C:\Program Files (x86)\Microsoft Office\root\Office16

  • Outlook 2013: C:\Program Files (x86)\Microsoft Office\Office15

  • Outlook 2010: C:\Program Files (x86)\Microsoft Office\Office14

  • Outlook 2007: C:\Program Files (x86)\Microsoft Office\Office12

If any of the above directories do not exist, try without " (x86)" in the path.

  1. Open "SCANPST.EXE".

  2. Select Browse to select the Outlook Data Files you want to scan. These will be stored at one of the following locations:

    • %userprofile%\Documents\Outlook Files

    • %localappdata%\Microsoft\Outlook

  3. Choose "Start" to begin the scan.

  4. If the scan finds errors, choose "Repair" to start the process to fix them.

  5. When the repair is complete, start Outlook with the profile associated with the Outlook Data Files you just repaired.

Delete Original Data Files

If repairing the Outlook data files didn't help, you can try deleting and recreating them.

  1. Close the Outlook application.

  2. Open File Explorer (Windows Key + E).

  3. Navigate to the following two folders on your machine by copying and pasting them into the path bar at the top:

    • %userprofile%\Documents\Outlook Files

    • %localappdata%\Microsoft\Outlook

Don't worry if one of the folders doesn't exist.

  1. Delete all of the files that have ".pst", ".nst" and ".ost" extensions.

  2. Empty the Recycle Bin.

Create New Data Files

  1. Open Run (Windows Key + R).

  2. Type "outlook /profiles" and press enter. A dialog box from the Outlook app should open.

  3. In the dialog box, click "Options > >".

  4. Click "New…".

  5. Give the profile a name and click "OK". You should be able to call it "Outlook", but if not you can call it something else like "Outlook 2".

  6. Follow the usual process of adding a new mailbox to recreate the data files and restore all of your emails.


You should now be able to launch Outlook without any problems. For further help, please see the official Microsoft documentation.