Since Word opens in Safe Mode, the most likely cause is an add-in loading during normal startup. Use this order:
- Start Word in Safe Mode
- Press Windows + R.
- Type winword /safe and press Enter.
- Confirm the title bar shows Word (Safe Mode).
- Disable Word add-ins
- In Word Safe Mode, go to File > Options > Add-Ins.
- In the Manage list, select Word Add-ins and click Go. If that option is not present, select COM Add-ins and click Go.
- Clear one add-in, click OK, then close Word.
- Start Word normally.
- If Word opens normally, the disabled add-in is the cause. Leave it disabled, remove it, or install an updated version from the add-in vendor.
- If Word still triggers the reinstall behavior, repeat and disable the next add-in. Also check both Word Add-ins and COM Add-ins.
- Repair Office
- If disabling add-ins does not fix it, run an Office repair.
- The documented guidance is to try a Quick Repair first, and if that does not help, use Online Repair.
- A Microsoft Q&A recommendation for Word startup failures is to open Settings > Apps / Installed Apps, find Microsoft Office / Microsoft 365, choose Modify, then run Online Repair.
- Install Windows updates and update device drivers
- In Windows 10, go to Settings > Update & security > Windows Update.
- Select Check online for updates from Microsoft Update.
- Install available updates.
- If the issue continues, update drivers for the video card, printer, mouse, and keyboard.
- If Word still fails, use Word’s startup troubleshooting switch
- Press Windows + R.
- Type winword /a and press Enter.
- This starts Word without loading add-ins and global templates automatically and helps isolate startup problems.
- Registry reset is available, but use caution
- Microsoft documents a method to delete the Word Options registry key if startup problems continue.
- This is a higher-risk step because incorrect registry changes can cause serious problems. Back up the registry first.
Based on the symptoms, the best workaround is to keep using Safe Mode long enough to disable add-ins, then test normal startup. If that does not resolve it, the next best fix is an Office repair.