ODBC System DSN does not show up in cnnection’s Source/Destination tab

If your ODBC DSN does not show up in the UnitySync connection Source or Destination tab drop-down option, you have likely created the DSN on the wrong version (32-bit vs 64-bit).

UnitySync ODBC connections require the use of 64-bit ODBC DSN’s. (Pre v2.1 required 32-bit)

**If you have just upgraded from a pre v2.1 version, any existing ODBC connection will use a DSN created with 32 bit ODBC. When looking at this connection in the current version UI the Source or Destination tab, you will see the DSN drop down box is empty. You must recreate the System DSN using 64 bit.

To create a 64 bit DSN, go to Control Panel > System and Security >Windows tools. Select ‘ODBC Datasources 64-bit’. From here, create a System DSN for your database using the appropriate ODBC driver. Once created, this DSN should now appear in your UnitySync connection Source or Destination tab.

Reference this article for other details about 64-bit vs 32-bit:
http://robertoschiabel.wordpress.com/2008/02/28/windows-x64-32bit-odbc-vs-64bit-odbc