What is the best hard drive for backing up with TIme Machine on my 2015 Macbook Pro? Are they all MAC compatible? SSD or HDD? I want to spend under $100 and prefer not to have to reformat to use with MAC. I use WINDOWS too.

Hi TinaJayneL,

You will have to reformat nearly any external drive you purchase, whether they are marketed as compatible with Mac or not. This is because Time Machine uses APFS (or Mac OS Extended Journaled, in older versions of macOS) as its filesystem, and Windows cannot interpret those formats natively.

If you want to use the drive for both Time Machine backups and general-purpose use, I would recommend using Disk Utility to partition the drive:

IMPORTANT: In step 7, choose your storage size carefully. You can't change the amount of space given to the general storage partition unless you delete it and recreate it.

1. Open Disk Utility, located in Applications -> Utilities.
2. In Disk Utility, select View -> Show All Devices.
3. Connect your external drive.
4. Select the top level of the external drive and click Erase. Assuming you're running macOS Monterey (12.1), choose these options, then click Erase:
   1. Name: Whatever you want (this will be for your Time Machine backups)
   2. Format: APFS
   3. Scheme: GUID Partition Table
5. When the erase is complete, click Done.
6. Select the top level of the external drive and click Partition. If you're asked to add an APFS volume instead, click Partition to confirm your intent.
7. A pie chart should appear. Click (+), then select how much space the second partition should occupy. This will be your general storage partition (not used for Time Machine).
8. For the second partition, choose ExFAT as the format, and give it a unique name. This format is fully supported by both Windows and macOS.
9. When you're satisfied with the drive layout, click Apply to create the new partition.

Unlikely you'll find a good quality external SSD large enough to backup your Mac for under $100. You will be able to find a mechanical HDD however.

You'll want a drive that is at least twice the size of the hard drive in your Mac. So if your Mac has a 512 GB drive, you'll want a 1TB drive for backups.

Since Time Machine backups don't need super high speeds from an SSD, a regular mechanical HDD should work well enough. As mentioned it will need to be formatted into HFS+ or APFS for Time Machine to use it.

clic here-> 1TB External HDDs - Amazon.com

a few more limitations: Time machine backs up all MacOS drives. But Time machine will not back up ExFAT or NTFS Windows drives, because they do not provide the MacOS data structures needed to determine instantly what needs to be backed up. You will need a separate backup system for your Windows drives.

Time machine does its work at low priority in the background, so that you can continue to do your important work. This means you should not pay extra for a Time machine backup drive that is FAST. A less expensive rotating magnetic drive will work just fine.

Drive enclosures that contain their own Power supply, rather than rely on Bus Power, are more stable and more reliable in the long run.

Hi,

You can't TimeMachine backup on NTFS or ExFAT drive, however only APFS and Mac OS Extended (Journaled) one.