Try installing the latest .NET Framework Runtime:
https://dotnet.microsoft.com/en-us/download/dotnet-framework/net48

If the installer says your .NET Framework is up to date, try uninstalling and reinstalling it.

If that doesn't work for you, take a look at this issue:
https://github.com/dotnet/wpf/issues/8056

Some users have reported that it's caused by some Windows update. Uninstalling it might fix the problem.