I have just purchased a new 2Tb Seagate HD to use on my iMac.
At present it is formatted for Windows (NTFS)
How do I reformat the disc to operate as my external back-up in Time Machine?
Open Disk Utility, select your new drive, add a partition and format it with Mac OS Extended-Journaled with the GUID partition table (from the OPTIONS button).
The third paragraph contains acceptable formats. The preferred on is what keg55 suggested.
Disks You Can Use
thank you for your reply and help. All up and running now.
Retrieving data ...