I have a C# application using Office.Interop.Excel which worked fine on Windows 10 and stopped working after upgrading to Windows 11. Any idea on how to fix this?
1 Answers
It seems your Windows registry keys were corrupted while upgrading to Windows 11. I'd recommend repairing MS Office applications for restoring the Windows registry keys. This also can be caused by installing a newer version of Microsoft Office, and then removing it and installing an older version instead. There are other ways this could happen.
You can try editing the keys manually as described below:
Start-->Run --> regedit --> HKEY_CLASSES_ROOT-->TypeLib-->{00020813-0000-0000-C000-000000000046} --> 1.8/1.7 - Delete the old one, but don't forget to export for any emergency cases.
If it was not successful, you can try to repair your Office from the control panel. Then, try again. If the problem still exists, you can completely uninstall, reboot, and then reinstall Office.
Here are some similar threads you can refer to:
- unable to cast COM object of type 'microsoft.Office.Interop.Excel.ApplicationClass' to 'microsoft.Office.Interop.Excel.Application'"
- How to solve “Unable to cast COM object of type Microsoft.Office.Interop.Excel.ApplicationClass’ to interface type ‘Microsoft.Office.Interop.Excel._Application’”
- How to solve “Unable to cast COM object of type Microsoft.Office.Interop.Excel.ApplicationClass' to interface type 'Microsoft.Office.Interop.Excel._Application'”
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