Permissions Gone with Monterey Upgrade?

Any ideas on this one? After several years of skipping upgrades, I finally brought my 2016 MBP up to Monterey, and have been enjoying it quite a bit, until I tried to use SuperDuper to do my standard back up routine - an incremental backup to an encrypted image on an external drive.

I could mount the image just fine (password was in my Keychain), but it came up as read-only, and SuperDuper would not allow me to select it as a destination. I changed permissions under “Get Info,” to no avail. I think I had originally created the image on another machine, so I hooked the external drive up to that machine and changed the permissions to “everybody can read and write.” Seemed to succeed. But when I connected it to my MBP and mounted the image, even though “Get Info” says I have read / write permissions, it opens as read only.

On top of this, my Time Machine password seems to have disappeared out of my keychain. Always mounted just fine when I plugged it in, but now it won’t, and the password entry in my keychain is outdated.

Weird. Thanks!


Check out this blog post.

Thanks! But I should have noted that I’m not trying to make bootable backups. So I don’t think that post resolves my issue.


I`m not familiar with “SuperDuper”, but the filesystem of macOS has changed somewhere between 2016, and Monterey.
So it would be, at least for me, a more surprise, if you could use those backup without any changes, than what you are experiencing right now.
I would always recommend to keep up with the updates of an OS, as long as there are no special needs (an important app, not running under a new OS!).
So I would “just” do a new setup, and continue from that point.
If you can still read the files on your old backup, consider keeping them for a while, just to be save.

1 Like

Step one is to buy a new external disk drive and set it up according to SuperDuper’s instructions on the updated Mac. That should provide you with an up-to-date backup copy of your system.

Since you still can read the old disk, put it “on the shelf” and keep it as a pre-upgrade backup in case you need it for whatever reason. External disks do not last forever and should be retired in favor of newer bigger faster less expensive disk drives.

So let me rephrase my question:

Is it a known issue that read-writable disk images created under a previous OS (Catalina) become read-only under Monterey? To the extent that the permissions under “Get Info” show that I have read-write status, but it is still read-only? I mean, that seems like a fairly serious “whoops.” If so, is there a workaround?

If it is not a known issue, and just the technology gods frowning upon me, so be it.

I will reiterate - I am not trying to create a bootable backup. I had already tracked with SuperDuper’s “long strange trip” around that issue and decided I didn’t need to bother with it.



A quick internet search reveals a few forum posts about problems with encrypted disk images in Monterey. This post had the best details:

FWIW, I just tested my encrypted disk image, which I’ve used under Monterey but not on my new M1 Mac, and it’s fine. Apple Partition Map, HFS+, disk image located on my boot drive.

The work around seems to be just make a new disk image and move the files into it. They seem to be backwards compatible with earlier macOS versions.

1 Like

Thanks for pointing me there! My Duck Duck Go skills didn’t uncover that.

I’ll have to set things churning overnight to create the new backup images (2 different drives that I rotate between home and office locations). Annoying, but manageable.

Thanks again!