Outlook Freezing

Quick Fix

1. Press Ctrl+Shift+Esc to open Task Manager, end any stuck Outlook processes. 2. Restart Outlook. 3. If it freezes again, run Outlook in safe mode by holding Ctrl while launching or typing outlook.exe /safe in Run dialog.

What it Means

Outlook freezing means the application stops responding, often due to add‑ins, corrupted data files, or resource contention. The error shows up as a blank window or a “Not Responding” dialog.

Possible Causes

• 1
  Heavy or corrupted add‑ins
• 2
  Outdated Office updates
• 3
  Large or corrupt PST/OST files
• 4
  Insufficient RAM or CPU
• 5
  Conflicting antivirus scans

Step-by-Step Solutions

1. Update Office

   Open any Office app, go to File > Account > Update Options > Update Now. This ensures Outlook has the latest patches that fix known freezes.

2. Disable Add‑Ins

   Open Outlook, go to File > Options > Add‑Ins. At the bottom, click Go next to Manage COM Add‑Ins. Uncheck all add‑ins, restart Outlook, and re‑enable one by one to find the culprit.

3. Repair PST/OST

   Close Outlook, locate ScanPST.exe (usually in C:\Program Files\Microsoft Office\root\Office16). Run it, browse to your PST/OST file, and click Start. This fixes corruption that can cause freezes.

   "C:\Program Files\Microsoft Office\root\Office16\ScanPST.exe" "C:\Users\User\Documents\Outlook Files\Outlook.pst"
4. Clear Cache

   Navigate to C:\Users\User\AppData\Local\Microsoft\Outlook and delete all .ost files. Restart Outlook to rebuild the cache.

5. Check Resources

   Open Task Manager, check CPU and Memory usage. If Outlook uses >80% CPU or memory is low, close other programs or upgrade RAM.

Commands You Can Try