Can't mount encrypted disk images after Monterey upgrade

[djc6]

I have some encrypted disk images I've been using since 2007 to store health, financial records, etc.. and I can't open them since I moved to macOS 12. I waited until 12.1 avoid some of these bugs.

I just get a message "The disk image couldn't be opened - The disk image is corrupted" when I click on the .dmg file. I have backups in time machine and backblaze, I can't open the backups either.

I did notice that I can "hdiutil attach <path to dmg>" in Terminal - and it prompts me for the password, mounts the DMG and then I can access everything normally via Finder. So I don't believe the disk images are corrupt. This same issue is happening to several encrypted disk images I have.

Any ideas what the problem is? This is only similar post I found: https://forums.macrumors.com/threads/opening-files-on-encrypted-images.2324837/

 

[BrianBaughn]

Just for info purposes…what were the settings of the disk images (format, encryption, partitions, image format)?

 

[djc6]

According to Disk Utility and "hdiutil imageinfo"

HFS+ Journaled format, AES-128 encryption, single partition, UDRW image format

Also interesting is "hdiutil isencrypted <path to dmg>" output. I noticed all the images I cannot open report "encrypted-file-version: 1" and the images I can open are "version: 2"

The oldest images are from April 2007 and I've been using them continuously - Created on my TiBook at the time, presumably MacOS X 10.4 Tiger.

 

[BrianBaughn]

To be safe I'd just create new images…but I don't use them like that and don't know if there's a better way to achieve the security.

 

[djc6]

To be safe I'd just create new images…

I made new images; took it as an opportunity to use sparse image instead of fixed size read/write images. The new encrypted images also show up as "version: 2" in "hdiutil isencrypted" output. I'm guessing Monterey Finder isn't capable of opening anything else.

 

[Fishrrman]

OP:

My suggestion for storing these older files.
(you won't like it)

DO NOT encrypt them, put them into a dmg file, a sparse file, or any other scheme like that.

RATHER, just store them on an UNENCRYPTED drive in simple finder format, a regular folder/file hierarchy.

Then, if security is an issue, hide the drive in a safe place, or store it in an actual safe or strongbox (possibly a fire-resistant box that is lockable).

WHY?
Because you WANT old files to be easy to "get at" if you need to look back at them.

You have found out right now why trying to "protect" them can lead to problems that KEEP YOU from accessing them.

Keep it simple -- retain access...!

 

[djc6]

They're not older files. The encrypted disk image is old - but the files inside the image are current. I reference add/replace the files often. I can still access the files, I just need to mount the image via Terminal first.

Also, having had computer physically stolen twice in life already - no way I'm not encrypting anything sensitive. Don't want a physical theft crime to turn into an identity theft crime on top of that! My Time Machine backups are encrypted too should they snag my external drive next time. Backblaze is so I still have backups if the time machine drive is stolen, or if house burns down.

 

[izzyamar]

Hey there - I know this is a sort of old post to reply to, but I was wondering if you'd been able to sort out why that encrypted dmg file wasn't mounting? I have a friend running into the same issue and I'm trying to troubleshoot. They have an encrypted dmg file that was created in Tiger, and can't open it in anything beyond Catalina. Would love to know if there's a solution (other then creating a new file, or using an old machine every time they need access to files in that dmg).

Thanks!

 

[djc6]

Hey there - I know this is a sort of old post to reply to, but I was wondering if you'd been able to sort out why that encrypted dmg file wasn't mounting? I have a friend running into the same issue and I'm trying to troubleshoot. They have an encrypted dmg file that was created in Tiger, and can't open it in anything beyond Catalina. Would love to know if there's a solution (other then creating a new file, or using an old machine every time they need access to files in that dmg).

Thanks!

Try the "hdiutil attach <path to dmg>" in Terminal suggestion above - that worked for me.

I then made a new encrypted disk image and copied files into that. Its just that the old encrypted disk image format isn't supported in Finder anymore.

 

[Smarky]

Edit: I posted in the wrong thread sorry, can't find a delete button.

Hdiutil attach works for me though, so thanks, not sure why I can't mount anything without using that.