My Outlook is frozen. I can't open it.

Outlook freezing or not opening is commonly caused by outdated updates, problematic add-ins, corrupted data files, antivirus integration, or a damaged Outlook profile.

Follow these steps in order:

1. Install the latest Windows and Office/Outlook updates

• Make sure Windows Update is set to install important and recommended updates.
• Install all available Windows and Office updates, then restart the PC.
• For Office, see Install Office updates.

2. Start Outlook in Safe Mode and disable add-ins Safe Mode starts Outlook without add-ins and can show if an add-in is causing the freeze.
3. Press Windows key + R.
4. Type: Outlook /safe and select OK.
5. If prompted, accept the default profile and enter the account password.
6. If Outlook opens in Safe Mode, disable add-ins:
   • File > Options > Add-ins.
   • At the bottom, ensure Manage = COM Add-ins, then select Go.
   • Clear all check boxes for the listed add-ins and select OK.
   • Close Outlook and start it normally (without /safe).
7. If Outlook now opens, re-enable add-ins one at a time, restarting Outlook each time, until the problematic add-in is found. Leave that add-in disabled.
8. Repair Office If Outlook still won’t open or keeps freezing:
9. Close all Microsoft 365 apps.
10. Open Control Panel > Programs and Features.
11. Find Microsoft Office/Microsoft 365, right-click it, and choose Change.
12. Run a repair, then restart the PC and try Outlook again.
13. Repair Outlook data files Corrupted data files (.pst/.ost) can prevent Outlook from opening or cause freezes.
14. Exit Outlook.
15. Run the Inbox Repair Tool (SCANPST.EXE) as described in Repair Outlook Data Files (.pst and .ost).
16. After repairs complete, start Outlook again.
17. Create and use a new Outlook profile If the profile is corrupted, Outlook may not open.
18. Follow the steps in Create an Outlook profile to create a new profile.
19. Start Outlook and choose the new profile in the Choose Profile dialog.
20. If Outlook opens normally with the new profile, the old profile is corrupted. Use the new profile going forward. If removing the old profile, back up data files first because cached offline content is removed when a profile is deleted.
21. Check antivirus integration Some antivirus products integrate with Outlook and can cause freezes.

• In the antivirus settings, disable Outlook-specific integration or Outlook add-ins (do not disable real-time protection entirely unless instructed by the antivirus vendor).
• If needed, contact the antivirus vendor for instructions on excluding Outlook integration.

7. Perform a Selective Startup (clean boot) If another program is conflicting with Outlook:
8. Open Control Panel > System and Security > Administrative Tools > System Configuration.
9. On the General tab, select Selective startup and clear Load system services and Load startup items.
10. Then select Load system services again, select OK, and restart.
11. If the problem reoccurs, use the Services and Startup tabs to disable items and re-enable them one by one until the conflicting service or startup item is identified, as described in the clean boot procedure.

If Outlook still will not open after these steps, use the Classic Outlook Advanced Diagnostics troubleshooter (where available) to automatically check for common causes.

References:

• Outlook not responding error or Outlook freezes when you open a file or send mail
• Outlook not responding, stuck at "Processing," stopped working, or freezes
• I can’t start Microsoft Outlook or receive the error “Cannot start Microsoft Outlook. Cannot open the Outlook Window”
• What to do when Outlook will not open on my PC? - Microsoft Q&A
• Outlook Freezing and Not Responding and Not saving changes when ending the task - Microsoft Q&A