Oulook loses after opening

For classic Outlook for Windows, first start Outlook in Safe Mode; if it remains open, disable its COM add-ins and re-enable them individually to identify the one causing the shutdown.^1^

Since restoring the PST did not help, start by testing causes outside the data file.

1. Test Outlook without add-ins

1. Close Outlook.
2. Press Windows key + R.
3. Enter:

      Outlook /safe
   

4. Select the profile if prompted.

If Outlook now stays open:

1. Go to File → Options → Add-ins.
2. At the bottom, select COM Add-ins, then Go.
3. Clear every enabled add-in and select OK.
4. Restart Outlook normally.
5. Re-enable add-ins one at a time, restarting Outlook after each one. Remove or update the add-in after which the problem returns.^1^

If Safe Mode also closes within ten seconds, continue below.

2. Repair Microsoft 365

1. Close all Office applications.
2. Open Control Panel → Programs → Uninstall a program.
3. Right-click the Microsoft 365 installation.
4. Select Change → Online Repair.
5. Complete the repair, restart Windows, and test Outlook.^2^

Online Repair or update removal may require administrator approval on a work-managed computer.

3. Test a new Outlook profile

Do not delete the existing profile or PST during this test.

1. Close Outlook.
2. Open Control Panel → User Accounts → Mail.
3. Select Show Profiles → Add.
4. Enter a new profile name and configure the Microsoft 365 account.
5. Set Outlook to prompt for a profile, or set the new profile as the default.
6. Start Outlook using the new profile.

If the new profile remains open, the original Outlook profile is damaged or misconfigured. Keep the original profile until any locally stored data has been backed up or transferred. Microsoft warns that removing a profile also removes its associated data files.^1^

4. Check for the matching Office identity crash

Open Event Viewer → Windows Logs → Application and inspect the Outlook failure. A documented issue applies only when Event 1000 or 1001 contains:

• Faulting application: OUTLOOK.EXE
• Faulting module: mso20win32client.dll
• Exception code: 0x01483052

For that exact signature:

1. Sign out of Office from another Office application.
2. Close all Office applications.
3. Sign back in and test Outlook.
4. Update Microsoft 365 to a current build.

Microsoft identified this failure as a blank Office identity EmailAddress value and fixed it beginning with Current Channel Version 2209 Build 15629.20156 and Semi-Annual Enterprise Channel Preview Version 2208 Build 15601.20158.^3^

Avoid manually editing that registry value unless directed by Microsoft Support; the supported sign-out/sign-in and update methods should be used first.

Conditional Windows 11 POP issue

Only consider KB5074109 if all of these are true:

• Windows 11 is installed.
• This is classic Outlook.
• The profile uses a POP account.
• Settings → Windows Update → Update history shows KB5074109.
• Outlook hangs or freezes rather than cleanly exiting.

That combination matches a documented Windows-update issue. Check Microsoft’s support notice before rollback: Classic Outlook POP account profiles hang and freeze after Windows 11 update to KB5074109. A quick clean exit is not the documented symptom, so do not uninstall the update merely because Outlook closes.^4^

If the conditions match and Microsoft still lists removal as the workaround, treat rollback as temporary: uninstalling a cumulative update may remove security and reliability fixes. Ensure recovery options are available, obtain administrator approval, and install Microsoft’s replacement or fixed update promptly.

If Outlook still closes

Run the Classic Outlook Advanced Diagnostics troubleshooter from the Microsoft Support crash article. It requires Windows 10 or later, must run on the computer containing classic Outlook, and does not support new Outlook.^1^

If the New Outlook toggle is enabled, these classic Outlook procedures do not apply; use the separate new Outlook troubleshooting route instead.

References

1. Outlook crashes or stops responding when used with Office 365 | Microsoft Support
2. How to troubleshoot issues that cause Outlook to crash or stop responding when used with Microsoft 365
3. Outlook closes shortly after it is opened | Microsoft Support
4. Outlook Freezing and Emails Disappearing - Microsoft Q&A