Thanks for joining the discussion and sharing the things you've done to resolve the problem, @tb38,

If the QuickBooks Tool Hub doesn't fix the error when opening QuickBooks, run the Repair Tool. This utility resolve common errors in the software. Perform the steps below:

1. Create a back up your company file beforehand to avoid any accidental data loss.
2. Reboot the computer and tap the Windows Start menu.
3. Find Control Panel on the search field or select it from the list.
4. Press Programs and Features then Uninstall a Program.

   Note: If you don't see Programs and Features, select Programs instead. Then select Program and Features.

5. Pick QuickBooks from the list of Programs, then press Uninstall/Change.
6. Click on Continue, or Next. then Repair.
7. Press Next again then wait for the tool to start its diagnosis.
8. Hit Finish when done.

To learn more about repairing the program and the complete instructions, go to this link: Repair your QuickBooks Desktop for Windows.

If you get the same problem after this troubleshooting, I recommend reaching out to our Technical Team immediately. Our representatives can run some database fixes and diagnosis to identify underlying issues with this unexpected behavior.

Here's how to get support:

1. Go to your QuickBooks Home page, then click the Help menu at the top.
2. Choose QuickBooks Desktop Help from the drop-down.
3. Hit the Contact us icon.
   

Kindly update me on how things go by adding another comment below. I want to make sure you're all set, and I'm here if you need further guidance. Have a great day! All the best.