Formatting external HD for Monterey

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Formatting external HD for Monterey

I need to format an external hard disk for backup / Time Machine purposes.

I understand that starting with Big Sur, Mac OS Extended (Journaled) is no longer the default when using Time Machine and that I should opt for APFS.

I also have read that an external HD formatted in APFS will not mount on a pre Big Sur system.

I have a couple of old Macs limited to High Sierra. Thinking of keeping my options open in that

maybe some time in the future I’ll want to connect the HD to the older Macs, I should format the HD

in Mac OS Extended (Journaled).

Basically, is there any harm in formatting the external HD in Mac OS Extended (Journaled) for Monterey 12.2.1.?

Many thanks.

MacBook Pro 16″, macOS 12.2

Posted on Mar 9, 2022 2:41 AM

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Answer 1

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PRP_53

Level 10

91,243 points

Mar 9, 2022 3:28 AM in response to J Soap

HFS Journaled / GUID or APFS / GUID can be read and written to in Mojave macOS 10.14 and above.

Time Machine Backup in Catalina can use either APFS / GUID or APFS / GUID

Time Machine Backup in Big Sur and Monterey ( as a New Setup of TM Backup ) will default to APFS / GUID.

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Answer 2

Mar 10, 2022 8:45 AM in response to J Soap

High Sierra is the oldest OS X that supports APFS and its system boots from both Mac OS Extended and APFS (AFAIR it defaults to APFS in SSDs).

I'd recommend formatting data disks as APFS (SSD) or Mac OS Extended (HDD) with GUID partition scheme (APFS is slow on HDDs, especially if used for booting). I use Carbon Copy Cloner for backups so I can't comment on best Time Machine disk format with old Macs.

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Formatting external HD for Monterey

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