1. Do all the Windows updates
2. Reinstall active MS .NET Runtime 8.0.22 or later: https://dotnet.microsoft.com/en-us/download/dotnet/8.0
3. Start Rhino and test

In order for us to diagnose the issue, please follow these steps using Rhino 8.26 or later:

1. Right click on Windows Start > Run
2. Paste C:\Program Files\Rhino 8\System\Rhino.exe /debuglog and click “Ok”.
3. Exit Rhino
4. Navigate to your Documents folder, and send us both the RhinoDebugMessages.txt and RhinoDotNetTraceLog.txt files.
5. Zip and email to tech@mcneel.com with a description of your problem. Or submit the Zip using our upload tool.

If Rhino will still not open without this error, modify the Rhino shortcut with the /netfx switch. Be sure to add a space before /netfx.

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Add this to the Rhino 8 shortcut as show above. /netfx initializes .NET framework 4.8. Now open Rhino with the short cut.

For additional help, email Technical support at tech@mcneel.com. Include your Rhino System Information: in Rhino type SystemInfo command. Copy and paste the text results into your reply

Solution 1: Run a “Repair” on the 64-bit Rhino in Control Panel > Programs and Features to correct the error.

Solution 2: If you have ShapeDiver v1.9.1 for Grasshopper installed, run the TestPackageManager command, and update ShapeDiver to v1.92-beta.1 or above.
(ShapeDiver does not cause this error for Rhino 7.)