Choosing MAPI Profile does not update registry correctly in 64-bit OS
Not running MClient.exe as Administrator
Resolving the problem
1. Open GENSRVNT\Bin directory.
2. Right click on MClient.exe
3. Select Run As Administrator
4. Change MAPI Profile under Gateways.
Issue occurs only on systems before 5.3.1. 5.3.1 Executables are set to Run As Administrator