...

Summary

When starting the Performer Suite an error could occur.

Error

System.MissingMethodException: Method not found: '!!0[] System.Array.Empty()'. 

Cause

Your .NET 4.6.1 Framework version is too low. It is needed to display the graphic interface of the Performer Suite.

Solution

Install the latest .NET Framework 4.8 (4.8.1 is currently not recommended)

Download: https://dotnet.microsoft.com/download

Further information

Install guide: https://docs.microsoft.com/en-us/download/dotnet/framework/install/-framework

Further information

Want to know find out which .NET version you have installed?
https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/how-to-determine-which-versions-are-installed