The following code works on Windows 10 64bit in Omnis Studio 5.1 Register DLL ('kernel32.dll','GetEnvironmentVariableW','JCC') Call DLL ('kernel32.dll','GetEnvironmentVariableW','COMPUTERNAME',vComputerName) Returns vError but it does not work on Windows 10 64bit in Omnis Studio 10.22 Any suggestions why? Grzegorz (Greg) Pasternak