Problem :
If the created system DSN is not appearing on the GP Login Window, and if your operating system is 64-bit the problem is because of the 64-bit version of ODBC. Since GP is 32-bit, it cannot recognize the 64-bit system DSN created using 64-bit version ODBC.
Resolution :
Go to "C:\Windows\SysWOW64", find the "odbcad32.exe" and double click, and create the DSN as usual. Now the created DSN will appear on the GP Login Window.
If the created system DSN is not appearing on the GP Login Window, and if your operating system is 64-bit the problem is because of the 64-bit version of ODBC. Since GP is 32-bit, it cannot recognize the 64-bit system DSN created using 64-bit version ODBC.
Resolution :
Go to "C:\Windows\SysWOW64", find the "odbcad32.exe" and double click, and create the DSN as usual. Now the created DSN will appear on the GP Login Window.