If Rhino will still not open without this error, modify the Rhino shortcut with the /netfx switch. -
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.)