I have a 3TB drive that I have formatted and partitioned, with the idea that I would use the largest partition for Time Machine. The two smaller partitions show as possible choices to use --- but the large partition does not. They are all MacOS Extended journaled GUID.
I'm thinking I will have to repartition to the dang undocumented max size that will work. What is the largest working size known out there?
Mac mini, OS X Mountain Lion (10.8.2), Toshiba 3TB USB3 drive