Is Microsoft Outlook crashing when you open it, closing unexpectedly, or just refusing to open at all? Outlook crashes are one of the most disruptive productivity problems in the workplace. This comprehensive guide covers every fix for Outlook crashing or not opening, whether you’re using Outlook 2016, Outlook 2019, Microsoft 365, or the new Outlook for Windows.
Why Does Outlook Keep Crashing?
Outlook crashes are caused by several common issues: a corrupted Outlook profile or data file (PST/OST), a problematic add-in interfering with startup, an incompatible or outdated version of Office, a corrupted Windows user profile, insufficient system resources, or conflicts with antivirus software scanning the Outlook data file in real time. Each cause requires a different fix.
Fix 1: Start Outlook in Safe Mode
Outlook Safe Mode disables all add-ins, which is often the source of crashes. To open Outlook in Safe Mode, press Windows + R, type outlook /safe, and press Enter. If Outlook opens normally in Safe Mode, an add-in is causing the crash. Identify and disable the culprit: go to File → Options → Add-ins → Manage: COM Add-ins → Go and uncheck all add-ins. Re-enable them one at a time, restarting Outlook each time, until you find which one causes the crash.
Fix 2: Disable Problematic Outlook Add-ins
Add-ins from antivirus software, Zoom, Teams, Skype for Business, Grammarly, and other third-party tools are frequent Outlook crash culprits. With Outlook open (or in Safe Mode), go to File → Options → Add-ins. At the bottom, change the dropdown to COM Add-ins and click Go. Uncheck all non-Microsoft add-ins and click OK. Restart Outlook normally. If it no longer crashes, add-ins were the cause — re-enable them one by one to isolate the problematic one.
Fix 3: Repair Your Outlook Data File (PST/OST)
A corrupted PST (Personal Storage Table) or OST (Offline Storage Table) file is a primary cause of Outlook crashes. Microsoft provides a free repair tool called ScanPST.exe (Inbox Repair Tool). Find it at: C:Program FilesMicrosoft Office
ootOffice16 (or Office15 for older versions). Close Outlook completely, run ScanPST.exe, browse to your Outlook data file (default location: C:Users[username]DocumentsOutlook Files or AppDataLocalMicrosoftOutlook), and click Start. After the scan, click Repair to fix any errors found.
Fix 4: Create a New Outlook Profile
A corrupted Outlook profile is a common crash cause. Creating a new profile forces Outlook to rebuild its configuration from scratch. Go to Control Panel → Mail (Microsoft Outlook) → Show Profiles → Add. Create a new profile with a different name. Set it as the default and open Outlook. If Outlook works with the new profile, the old profile was corrupted — you can export emails from the old profile before deleting it.
Fix 5: Repair Microsoft Office
Corrupted Office installation files cause Outlook to crash on startup. Go to Settings → Apps → Installed apps, find Microsoft 365 or Office, click the three-dot menu → Modify → Quick Repair. Wait for Quick Repair to complete, then test Outlook. If still crashing, return and choose Online Repair — this re-downloads and reinstalls all Office components while preserving your data. Online Repair takes 15-30 minutes.
Fix 6: Update Microsoft 365/Office
Running an outdated version of Office can cause crashes, especially after Windows updates. Open any other Office app (like Word), go to File → Account → Update Options → Update Now. Install all available updates and restart your computer. Microsoft frequently releases stability fixes that address crash issues.
Fix 7: Check for Antivirus Interference
Some antivirus programs scan Outlook data files in real time, which can cause Outlook to crash or hang when accessing emails. Try temporarily disabling real-time protection in your antivirus and test if Outlook runs normally. If it does, add the Outlook data file folder as an exclusion in your antivirus settings: typically C:Users[username]AppDataLocalMicrosoftOutlook. Keep real-time protection enabled for all other folders.
Outlook Crashing: Quick Fix Checklist
- Start Outlook in Safe Mode (outlook /safe) to test for add-in conflicts
- Disable all COM add-ins and re-enable one by one
- Run ScanPST.exe to repair corrupted Outlook data files
- Create a new Outlook profile
- Run Quick Repair then Online Repair for Microsoft Office
- Update Microsoft 365/Office to the latest version
- Add Outlook data folder to antivirus exclusions
Frequently Asked Questions (FAQ)
Outlook opens then immediately closes — what causes this?
Outlook opening and immediately closing is usually caused by a corrupted Outlook profile, a problematic add-in, or a corrupted PST/OST file. Start with Safe Mode to isolate add-in issues, then try ScanPST to repair the data file, and finally create a new profile if both fail.
Will repairing Office delete my emails?
No. Running Quick Repair or Online Repair for Microsoft Office does not delete emails, contacts, or calendar items. For Exchange/Microsoft 365 accounts, all data is stored on the server. For POP3 accounts with local PST files, make a backup of the PST file before running a repair, just as a precaution.
Outlook still crashing after trying these fixes? Leave a comment with your Office version and whether Outlook shows any error message before crashing — our team will help you find the specific fix for your situation.