Excel will not run

Since Excel still fails after Safe Mode add-ins were disabled and after Online Repair plus reinstall, the next supported troubleshooting path is to check startup items, disabled items, and Windows conflicts.

1. Check whether Excel has disabled a component automatically
   • Open another Office app if available.
   • Go to File > Options > Add-ins.
   • In Manage, select Disabled Items > Go.
   • If Excel-related items appear, enable only what is necessary and test again.
   • If the problem returns after re-enabling an item, leave that item disabled.
2. Investigate Excel startup folders
   • Excel can automatically open files from the XLStart folder or an alternate startup folder.
   • A bad workbook or startup file in those folders can prevent normal startup.
   • Start Excel without opening workbooks from those startup folders and test again.
   • If Excel starts normally afterward, one of those startup files is the cause.
3. Perform a selective startup of Windows
   • A background application, process, or service can conflict with Excel.
   • Use selective startup (clean boot) in Windows to identify whether another program is interfering.
   • If Excel works in selective startup, re-enable services and startup items gradually to isolate the conflicting software.
4. Check Excel add-ins in the registry only if needed
   • Since COM add-ins were already disabled, the next documented step is checking Excel add-ins loaded through the OPEN registry values.
   • Warning: registry changes can cause serious problems if done incorrectly. Back up the registry first.
   • Open Run, type regedit.exe, and go to: HKEY_CURRENT_USER\Software\Microsoft\Office\<1x.0>\Excel\Options
   • For Microsoft 365 / newer Excel versions, 16.0 is used.
   • Look for REG_SZ values named OPEN, OPEN1, and similar.
   • Rename them by adding Renamed to the beginning, for example OPEN to RenamedOPEN.
   • Restart Excel normally.
   • If Excel starts, restore them one at a time to identify the problematic add-in.
5. Use the Excel automated troubleshooter
   • On Windows 10 or later, the Excel crash troubleshooter can automate Safe Mode isolation.
   • It can disable COM add-ins, disable Excel add-ins, move startup-folder files, and rename custom toolbar files.
   • Warning: it may modify the registry and move startup files, so back up the registry and startup-folder files first.
6. If Excel still does not start in Safe Mode or continues failing after these checks
   • The documented next action is to repair Office again if needed, but that has already been done.
   • At that point, the remaining supported path from the available guidance is isolating startup-folder files and Windows service/application conflicts through selective startup.

Given the steps already completed, the highest-value next actions are:

• check XLStart / alternate startup folder contents,
• run a selective startup (clean boot),
• then inspect OPEN / OPEN1 Excel registry add-in entries if the issue remains.

References:

• Excel not responding, hangs, freezes or stops working
• Open Office apps in safe mode on a Windows PC