Outlook Not Opening or Crashing on Startup – Easy Fixes

When Microsoft Outlook refuses to open or keeps crashing on startup, it usually points to corrupted profiles, faulty add-ins, or damaged data files. These issues interrupt workflow, stop you from accessing emails, and can cause complete account desynchronization. This step-by-step guide explains how to fix Outlook startup issues safely for versions 2016 through 2025.

Common Causes of Outlook Startup Crashes

• Corrupted Outlook profile or registry entries
• Conflicting or outdated COM add-ins
• Damaged OST/PST data files
• Outdated Office or Windows updates
• Faulty third-party antivirus or mail scanning software

1. Launch Outlook in Safe Mode

Safe Mode starts Outlook without extensions or custom settings, helping you isolate the problem.

1. Press Windows + R to open the Run dialog.
2. Type outlook /safe and press Enter.
3. If Outlook opens successfully, an add-in is likely the cause.
4. Go to File → Options → Add-ins → click Go next to COM Add-ins → uncheck all and restart Outlook normally.

2. Repair the Outlook Profile

Corrupted profiles often stop Outlook from launching properly.

1. Open Control Panel → Mail → Show Profiles.
2. Select your account and click Remove.
3. Click Add to create a new profile and re-enter your account details.
4. Choose “Always use this profile” and restart Outlook.

3. Repair Outlook Data Files (.OST / .PST)

If Outlook still fails, your data files may be damaged. Use Microsoft’s built-in repair tool:

1. Locate SCANPST.EXE in your Office installation folder.
2. Browse to your OST/PST file at:

   %localappdata%\Microsoft\Outlook

3. Click Start → Repair to fix any detected issues.

For detailed instructions, read our related article: Repair Outlook Data File (.OST/.PST) to Fix Sync Errors.

4. Disable Hardware Graphics Acceleration

In newer Outlook builds, hardware acceleration may cause graphics-related crashes.

1. Go to File → Options → Advanced.
2. Check the box for Disable hardware graphics acceleration.
3. Restart Outlook.

5. Repair Office Installation

If nothing works, your Outlook installation may be corrupted.

1. Go to Control Panel → Programs and Features.
2. Select Microsoft Office → click Change.
3. Choose Quick Repair (try Online Repair if that fails).

6. Update Windows and Office

Keeping Outlook and Windows up-to-date prevents compatibility and crash issues.

• Go to File → Office Account → Update Options → Update Now.
• Also run Windows Update to install pending system patches.

Related Articles

• Fix Outlook and Office 365 Sync Issues
• Email Setup and Configuration
• Repair Outlook Data File (.OST/.PST) to Fix Sync Errors

Conclusion

If Outlook won’t open or keeps crashing, start with Safe Mode to isolate add-ins, then repair your profile and data files. Most users resolve the issue without reinstalling Office. Keeping your software updated and limiting add-ins ensures a smooth, reliable Outlook experience.