I have 2 GTK# for .NET versions installed, 2.12.26 and 2.12.30. Is it safe to remove the older version?
I am assuming you are on Windows. The GTK# installers will use the same directory location so you may need to install GTK# 2.12.30 again. I would try uninstalling GTK# 2.12.26 first and see if everything works.
You can download a separate GTK# 2.12.30 installer for Windows if you need to.
Xamarin Inc., as a wholly-owned Microsoft subsidiary acting as a separate legal entity, adheres to the Microsoft Privacy Statement: Privacy & cookies