Why this happens
Outlook may get stuck due to:
A damaged Outlook profile or a problematic PST/OST file
An add-in blocking Outlook during startup
Cached sign-in details or connection settings causing conflicts
Security software interfering with Outlook as it loads
How to fix it
Start Outlook in Safe Mode (disables add-ins)
Press Windows + R, type:
outlook.exe /safe
Press Enter. If Outlook opens in Safe Mode, the issue is often caused by an add-in.
Disable add-ins (if Safe Mode works)
While Outlook is open, go to File > Options > Add-ins.
At the bottom, next to Manage: COM Add-ins, click Go, then disable add-ins one by one. Restart Outlook normally and test again.
Clear cached credentials
Old saved sign-in details can cause Outlook to hang.
Open Control Panel > Credential Manager
Remove saved entries related to Outlook or Microsoft Office (examples may include MicrosoftOffice16 or Outlook)
Restart your PC, then open Outlook again
Repair Office
If Outlook is still stuck, repair Office to restore missing or corrupted components.
Go to Control Panel > Programs > Programs and Features
Select Microsoft Office and click Change
Run Quick Repair first, and if needed, try Online Repair