I have a 3TB USB3 drive that I want to use between my Mac and Windows laptops. A 1.5TB partition will be used for Time Machine and another 1.5TB partition will be used by Windows for file storage. The Windows partition will be ex-FAT because I want the files to be read/write able from both machines. The drive will be swapped between the two machines periodically.
On what OS should I create the two partitions so that it's usable by both OSes? I started by creating partitions in Windows. The Mac can see the Windows partition but when I try to format the parition for Time Machine, Disk Utility says:
Volume Erase failed with the error: MediaKit reports not enough space on device for requested operation.