TimeMachine on new ext HD using Monterey reformats the drive to APFS

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TimeMachine on new ext HD using Monterey reformats the drive to APFS

Recently upgraded to Monterey 12.1 on my 2012 MBP and need to create a new Time Machine backup on a new 5TByte drive due to increasing failure of my old HD. On first use on the new drive Time Machine grabs and reformats the drive to APFS even though it was formatted to MAC OS Extended Journaled. This renders the drive useless for its primary intention as Finder will not let me copy anything to that new format. A waste of 4.5TByte of disk space.

Have rerun the process after erasing the new drive back to Mac OS Extended. Same result. Have let a full TM backup run and still unable to use the drive as a normal drive.

Have also tried simply copying the backupdb files off my old drive but after 6 hours it was still at the gathering files stage - not sure if that is the old drive misbehaving or just expected. Am keen to not stress that drive too much in case it dies entirely.

Any advice on how to solve the Time Machine setup on the new drive to both use it as a drive and also TM backup location.

Posted on Jan 26, 2022 8:13 AM

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Answer 1

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neuroanatomist

Level 9

50,029 points

Jan 26, 2022 9:27 AM in response to Lost_Pixel

I wouldn't call it flawed. If you're using an external drive, Apple expects that drive to be for Time Machine only. If that's the case, you just plug it in, select it when prompted, and you're all set. What you're trying to do (which is what I've done) is more complex than Apple intends, so there are more steps to get there.

There are multiple tutorials, e.g. https://www.macworld.com/article/235014/how-to-reserve-time-machine-space-on-an-apfs-drive.html

Note that partitioning is not what you want to do. You want to have ≥2 APFS volumes in the same container, with one volume dedicated to TM. An AFPS volume is not the same as a drive partition (in technical terms, because of the new format – in practical terms, the result is the same, i.e. you connect the external drive and you get ≥2 disks mounted on your desktop).

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Answer 2

Jan 26, 2022 8:27 AM in response to Lost_Pixel

Lost_Pixel wrote:

Recently upgraded to Monterey 12.1 on my 2012 MBP

MacOS 12 Monterey runs on MacBook Pro models from Early 2015 and later. If you somehow managed to install it on a 2012 MBP, I imagine you're setting yourself up for a wide variety of issues.

https://support.apple.com/en-us/HT212551

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Answer 3

Jan 26, 2022 9:03 AM in response to Lost_Pixel

You need to format as APFS and set up multiple volumes on the external drive using Disk Utility. That will erase the drive, but from there you'll be good. I have a pair of 5 TB external drives each with 5 volumes, 1 each for a TM backup of four Macs in the house (different sizes, all 2.5x the internal drive) and the remaining volume uses the rest of the space on the drive and is just for file storage. My RAID 1 NAS is set up the same way.

In theory, you can have one TM volume used by several Macs, but in practice the one that's used most will expand to take up most of the space over time, so having one volume per Mac limits the size of the TM backup (and TM manages that space, deleting the old files as needed).

Key thing is to have separate volumes for TM and general use. When you are prompted to select a TM backup drive, pick just the volume you want for that.

https://support.apple.com/guide/disk-utility/add-erase-or-delete-apfs-volumes-dskua9e6a110/mac

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Answer 4

Jan 26, 2022 10:58 AM in response to Lost_Pixel

Apple File System (APFS) was introduced for the Boot drive (if it was an SSD) in 10.13 High Sierra, and has been available for use on ANY drive since then. It is not a Time Machine-specific format, it is the new Mac drive format.

As long as your backup drive is being used by a Mac running 10.13 or later, files are perfectly recognizable and accessible as Apple File System Drives.

Time machine provides a separate mechanism for finding and restoring files. TimeMachine.app, located in the /Applications folder provides the "Star Wars" "back, back, back in time" interface, pictured here:

(drag and drop on preview so see larger and scroll)

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Answer 5

Lost_Pixel Author

Level 1

7 points

Jan 26, 2022 8:50 AM in response to Lost_Pixel

Just for clarity - TM insists on erasing the new drive in order to be able to use it. Have removed this drive from TM backup as well as NAS drive (in use as a temporary backup solution) which I understand does use APFS. On restart Mac OS recognises the attached drive and asks do you want TM to use it. Say yes and it does exactly the same asking either "Erase" or "Use a different volume".

How do you get TM to use the drive without erasing it?

I can continue to use the NAS volume when at home but this isn't the solution I want.

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Answer 6

Lost_Pixel Author

Level 1

7 points

Jan 26, 2022 9:11 AM in response to neuroanatomist

Thanks - I was suspecting the answer was something like this - the TM process is clearly flawed now without giving any support to those users like me with less or no technical knowledge. Not at all helpful. I couldn't find anything anywhere that tells you how to do this basic function. Also, it is contrary to Apple's own advice that APFS is best suited to SSDs rather than mechanical disks. I presume it is simply partition in Disk Utility to create the additional volume(s). Will give this a try.

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Answer 7

Lost_Pixel Author

Level 1

7 points

Jan 26, 2022 10:30 AM in response to neuroanatomist

That's great - Thanks.

It's a huge assumption and imposition by Apple to now let TM assume it has sole rights to a drive when it used to work on external disks just fine alongside normal usage. I'll read the link you attached and suspect I may need to start over - Just used partition and got going before I received your helpful article. Suspect APFS is new to many as well as me and it works quite differently than older formats. Stuff that used to work now simply doesn't.

Just changing the way things work with no explanation whatsoever and while not signposting any alternative is frustrating and not why I use Apple products. I was hoping to follow advice on how to migrate TM to a new drive and simply copy off my old TM backup to the new drive so I retain access to everything I had. A day lost sorting this - thanks Apple....

One downside is that, using external portable HDs (loads of video and photo work on the go - too much to use the main SSD in my MBP) means I guess, that you now have to eject both the TM and general volumes before you can unplug a HD. Two steps where you used to have just one. I know I'll end up unplugging the drive without ejecting both of the volumes properly - if that's what you need to do. Remembering to do one so you don't get the "Don't do this message....!" is hard enough.

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Answer 8

Jan 26, 2022 10:53 AM in response to Lost_Pixel

Just hold the option key as you drag one volume to the trash/eject, it will eject all mounted volumes on that drive. If you don't, MacOS will prompt you to eject just that one volume or eject all of them.

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Answer 9

Lost_Pixel Author

Level 1

7 points

Jan 26, 2022 11:45 AM in response to Grant Bennet-Alder

Thanks - The problem was with TM grabbing the whole of a new external HD for exclusive use when previous versions of Mac OS allowed both TM and files to be stored on the same drive. I couldn't find any clues of the cause of the problem or any solutions when I searched earlier. The solution has thankfully been provided by neuroanatomist. It is simple but not in any way intuitive.

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