Excel for Macbook "can't be opened" AND "unexpectedly quit" on launch

Question

I use Excel daily on my Macbook Pro (Mac OS Sonoma 14.6.1). Yesterday I attempted to open the application and got two error messages on top of each other: "The application 'Microsoft Excel' can't be opened." (with an "okay" button to close the pop-up) and "Microsoft Excel quit unexpectedly. Click Report to see more detailed information and send a report to Apple." (with an "Ignore" button and a "Report..." button.) See below for screen shot of these side-by-side:

Answer 1

Please don't go down the rabbit holes proposed by the AI answer bot.

The first point to be addressed is that your installation of Sonoma [14.6.1] is seriously behind on updates. Version 14.8.9 is the current release. That alone may provide the remedy but even if it doesn't it's pointless to chase symptoms when the OS is so far behind. Also, confirm that Office is fully updated – Use Help> Check for Updates in either program you can open.

If neither of the Office programs will launch go to Macintosh HD/Library/Application Support/Microsoft/MAU2.0/Microsoft AutoUpdate.app to launch Microsoft AutoUpdate [MAU] directly.

Answer 2

Try these steps in order.

1. Quit all apps first.
   • On the top toolbar, select each open app and choose Quit.
   • If an app will not close, press Command + Option + Esc, select the app, and choose Force Quit.
2. Reset Excel preferences.
   • Quit all Microsoft Office for Mac apps.
   • In Finder, select Go > Home.
   • Open Library. If Library is hidden, hold Option while opening the Go menu.
   • Open Preferences.
   • Drag com.microsoft.Excel.plist to the desktop.
   • Open Excel and test it.
   • If Excel still fails, quit Excel, move that file back to its original location, and continue.
3. Reset the secondary Excel preferences file.
   • Quit all Office for Mac apps.
   • In Finder, select Go > Home > Library > Preferences > Microsoft.
   • Drag com.microsoft.Excel.prefs.plist to the desktop.
   • Open Excel and test it.
   • If this fixes the issue, move that file to the Trash.
   • If not, restore it and continue.
4. Repair disk permissions.
   • Select Go > Utilities.
   • Open Disk Utility.
   • Select the primary hard disk.
   • Open the First Aid tab.
   • Select Repair Disk Permissions.
   • Then open Excel and test again.
5. Test with a new macOS user account.
   • Select the Apple icon > System Preferences > Accounts.
   • Select + to create a new account.
   • Create a test account, sign out, then sign in with that new account.
   • Open Excel.
   • If Excel works in the new account, the existing macOS user profile is likely the problem. The documented next step is to contact Apple support for the existing account.
6. If Excel still will not open, remove and reinstall Office.
   • This is the last documented step after the preference, permissions, and user-profile checks.

These steps match the documented causes for this startup failure: corrupted Excel preferences, background app interference, corrupted application files, or a corrupted user profile.

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References:

• "Microsoft Excel has encountered a problem and needs to close" when starting Excel for Mac