upgrading to Monterery, time machine in MacOS Extended format

DebB103 wrote:

How do I resolve this, then? Do I need to use a new external drive formatted in APFS before I migrate to Monterey? Can I copy and paste my previous time machine back ups onto an eternal using APFS?

I still use a HFS+ formatted time machine drive with out issue on macOS 12.3—

typically you are better off starting a new TM backup with the new macOS.

If you need to create a new backup from Mac - Apple Support

Transfer Time Machine backups from one backup disk to another

https://support.apple.com/en-ca/HT202380 —(seems to have been removed: try the 2/26/2021 archive)

https://web.archive.org/web/20210226200806/https://support.apple.com/en-ca/HT202380

—or try https://www.macworld.com/article/228862/how-to-transfer-a-time-machine-backup-to-another-backup-drive.html

If your new Mac inherits your backup history - Apple Support

If your new Mac inherits your backup history - Apple Support

3-2-1 Backup Strategy: three copies of your data, two different methods, and one offsite.

"migrate to Monterey?"

The most trouble free way to move to a new machine, is using the Setup Assistant on the initial boot of a brand new machine— you have one shot here. Set up your MacBook Pro - Apple Support

The second best way is use the Migration Assistant.

How to move your content to a new Mac Move your content to a new Mac - Apple Support

When I choose to upgrade an operating system from a previous major version (e.g. 11.*) to the next (e.g. 12.*), I make one last TM backup on the previous operating system, and then remove that drive, not letting the new operating system's TM backup touch that drive. The first backup and all remaining backups of the new operating system go on a new, clean APFS TM drive.

1. The rationale for this is I may wish to revert to the previous major (e.g. 11.*) operating system which I can do with that parked TM drive and booting into Recovery, but cannot do so if the newer operating system's TM backup has written to it.
2. When I take delivery of a new Apple Silicon Mac, I may want to use that previous TM drive during the initial setup process to restore all of my files, emails, and other settings from that TM drive.

The guideline for sizing TM drives is that they should be 2.5 - 3x larger than the internal startup drive of the Mac. That way, you are not prematurely running out of TM drive space.

In Monterey, Time Machine expects its drive to be formatted as APFS, not HFS+.