Hi Magdy, Thanks for posting here in Microsoft community, here’s what you can try.
First, Restart Excel, Close Excel and reopen it.
Next, Disable Add-ins, Start Excel in Safe Mode (hold Ctrl while opening) to see if an add-in is causing the issue.
Also try to Update Excel, Ensure Excel is updated to the latest version.
Check for Corruption, try opening another Excel file to see if it’s just that one document.
Repair Office, simply Go to Control Panel > Programs > right-click Microsoft Office > Change > Repair.
If the problem persists, you may need to reinstall Excel.
Hope this helps you out, let me know how it goes.
Chard