The installer of GroupWise 2014 R2 SP1 client on our Windows Server 2012 R2 Server (running Citrix) removed the MSVCP120.DLL and MSVCR120.DLL files from the C:\Windows\System32 folder. The result is the incapacity of login on anymore with Citrix clients or RDP clients and also throwing missing dll errors on the Win7LookAndFeelStartupApp.exe file while login on directly at the Windows server console.

The solution is to restore those 2 files from backup and reboot the server (we had to reboot the server twice in our case).

Please fix the client install so it doesn't do this and... therefore prevent heart attacks.