OS Sierra back up
Hi. I am wondering if someone knows a good hard disk works with Sierra 10.12.5. Thank you.
iMac 21.5″, macOS 10.15
Question marked as
Anything at least twice as large as the drive being backed up. Sierra isn't picky. At worst it may need to be reformatted with a GUID partion map with a MacOS Extended (HFS+) partion for time machine use. I think timemachine will prompt to do that automaticaly, but if not DiskUility can handle the partitioning. Partition a physical disk using Disk Utility on Mac - Apple Support
Note: if this is for a 2011 or older iMac I would suggest a Firewire800 drive. OWC (macsales.com) still sells those. For a 2012-2015 iMac instead look for a USB 3 drive.