APFS or Mac OS Extended Journaled for an external hard drive (SanDisk Prof G-Drive ArmourATD 5TB) to use with Time Machine

Sonoma and Time Machine Utility will require the Destination drive be formatted as APFS

Or, it will automatically reformat the New Drive into APFS / GUID Partition Map

Although you can use the Single Drive for two Separate Purposes - it is not suggested doing so.

Drives to fail and when that do, it is usually when you need the Backup at a Critical Time

For future purposes

To truly protect your non replaceable Data - have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive 

Time Machine requires that the entire drive be only used for Time Machine as it reformats the drive to APFS (Case-sensitive) and read only (except for Time Machine) the first time it uses it.

The reason is if the drive crashes the "other storage" will have no backup and be unable to be retrieved as your Mac's boot drive can be (unless it crashes at the same time which is highly unlikely).

Any recommendations as to what type of external hard drive to acquire for Time Machine backups as I have a new Macbook Air 15", M2 with lastest version of Sonoma. What specifications do I need to look for on the external hard drive (portable) to work with the M2 and Sonoma?

Joanne CW wrote:

Any recommendations as to what type of external hard drive to acquire for Time Machine backups as I have a new Macbook Air 15", M2 with lastest version of Sonoma. What specifications do I need to look for on the external hard drive (portable) to work with the M2 and Sonoma?

Thank you for your question

The M2 MacBook Air 15" computer has USB-C female ports

To connect an External Drive, it would be Best the External Drive come equipped with USB-C ( Male ) connectors on the Supple Cable

Having the drive configured this way would eliminate the requirement to have a USB-A to USB-C adapter

Though, having that adapter can be used it just becomes another accessory to be carried around and risks misplacement or loss

They Type of Drive I suggest would be at least 2 1/2 times Greater in Capacity than the Internal Drive of the computer.

Example would be - Internal Drive is 1 TB so get the External with a capacity of 4 TB

This will give the computer and Backup Drive a lot of space and avoid having to possible replace the external drive for something larger

Personally use only Solid State Drives ( SSD )

Brands - Do not use some unknown Brands and try going with those one may have seen suggested on the Forums

Samsung is often mentioned as are others

Thank you for the suggestions. A helpful start.

Welcome

Do come back to Apple Support Forums if or when you have additional questions