Excel isses

Start Excel in Safe Mode to isolate add-ins; if it still fails there, skip further repair attempts and proceed through updates to a complete Office uninstall and reinstall.

1. Test Excel in Safe Mode

1. Press Windows key + R.
2. Enter:

      excel /safe
   

3. Select OK.
4. Confirm that the title bar says Microsoft Excel (Safe Mode).

Safe Mode bypasses Excel and COM add-ins, startup folders, and certain custom settings that can cause a startup failure.^1^

If Excel opens in Safe Mode

Disable add-ins before returning to normal mode:

1. Select File → Options → Add-ins.
2. At the bottom, set Manage to COM Add-ins, then select Go.
3. Clear all enabled add-ins and select OK.
4. Repeat this for Excel Add-ins if that option appears under Manage.
5. Close Excel and open it normally.
6. If Excel now opens, re-enable add-ins individually, restarting Excel each time. Leave the add-in that triggers the error disabled, or obtain an updated version from its publisher.^2^

If Excel does not open in Safe Mode

Because Online Repair has already been completed, do not run it again.

1. Update Office through another working Office application, such as Word:
   • Open Word and create a blank document.
   • Select File → Account → Update Options → Update Now.
   • If necessary, select Enable Updates first.^3^
2. Install Windows and driver updates:
   • Windows 11: Start → Settings → Windows Update → Check for updates.
   • Install available updates and restart the computer.
   • If the failure remains, check the PC manufacturer’s support utility for updated display and other device drivers. Microsoft lists incompatible drivers as another cause of Office startup failures.^2^
3. Completely uninstall and reinstall Microsoft 365:
   • Back up any unsaved local files and confirm that the Microsoft account used for Office is available.
   • Run Microsoft’s uninstall troubleshooter on the affected PC.
   • Follow its prompts, and restart Windows when requested.
   • Reinstall Microsoft 365 using the same licensed account.

The troubleshooter supports Microsoft 365, Office 2021, 2019, and 2016 on Windows 10 or later; it currently does not uninstall Office 2024.^4^

If the error remains after reinstalling

Perform a clean boot/selective startup to determine whether another background program or service conflicts with Excel. If Excel works during the clean boot, re-enable startup items in groups until the conflicting software is identified.^1^

On a work- or school-managed computer, contact the organization’s IT administrator at this stage because update policies, security software, and installed add-ins may be centrally controlled.

References

1. Excel not responding, hangs, freezes or stops working
2. I get a "stopped working" error when I start Office applications on my PC | Microsoft Support
3. How to update Microsoft 365 or Office for Windows | Microsoft Support
4. Microsoft 365 subscription features aren't available in Office apps | Microsoft Support