Tahoe mistakes internal SSD APFS volume as encrypted and will not mount

In the end, I decided to re-install Tahoe 26.0 as outlined. It took a long time but seems to be working correctly.

[Edited by Moderator]

- Pie Lover

Thanks for the reply. I think that you're correct that the internal SSD uses hardware encryption tied to a unique key assigned to at the factory.

In my case, after the Tahoe installation, there was a mismatch in the APFS encryption as reported by Sequoia (none) and Tahoe (encrypted). In fact, Tahoe requested a non-existent password to mount the internal APFS volume. This is what I reported to Apple.

- Pie Lover

Good advice regarding sticking to the most common configurations.

I had previously checked FileVault and verified that it was turned off (in Tahoe). If I remember correctly, I had used a default admin account which doesn't login to iCloud to install Tahoe.

I plan to have another try installing Tahoe probably after a couple of maintenance updates. Here is my tentative plan:

1) With Sequoia, create a new APFS volume for Tahoe on the external SDD

2) Boot into recovery (using Sequoia on the internal SSD)

3) Recover Sequoia to the APFS volume for Tahoe (on the external SSD)

4) Set the startup disk to to boot from the external SSD

5) Recover user files and system settings using the Migration Assistant (from either the internal SSD or Time Machine)

6) Reboot without logging in to iCloud

7) Use System Update to upgrade from Sequoia to the most recent Tahoe update

8) login to iCloud after the Tahoe installation has completed

I'm hoping the above steps will avoid the difficulties that I encountered during my first attempt.

- Pie Lover

Usually, my first step would be to run First Aid in the Disk Utility. In my case, I couldn't even mount my device because macOS thought that it was encrypted.

From what you write, I find it suspicious that the drive stopped working precisely when you upgraded to Tahoe. If you are able, I would suggest reverting to Sequoia and re-testing, if for no other reason than backing up your data. Thinking back to macOS Monterey, I recall many reports of drives that had stopped working after an upgrade. For some, this was fixed by a subsequent maintenance update thus confirming that the problem was related to software/firmware.

- Pie Lover

During one of my attempts to install Tahoe, I noticed that File Vault was enabled by default. As you suggest, I was able to turn off File Vault once the installation completed.

- Pie Lover

Yes I did, but it still seems to me that there may be an issue with version 26.0 of Tahoe. I subsequently ran the First Aid command in Disk Utility to confirm that none of the volumes were corrupted. I ran Disk Utility both in Recovery and running under macOS.

I suspect that installing macOS Tahoe on an external SSD may not have been thoroughly tested.

- Pie Lover

Thanks very much for sharing your experience. I think that I had missed your reply when I replied to HWTech.

This is essentially the approach that I eventually followed except that I had to first install Sequoia on the external drive. I also ended up re-installing Sequoia on the internal drive to rectify a weird problem with Recovery. Prior to that re-install of Sequoia, Recovery could not find any of the required volumes on the internal SSD. I wonder if this was somehow related to my earlier attempts to install Tahoe. Maybe this also explains that the internal Sequoia looked like an encrypted APFS volume to Tahoe.

Going forward, I think that I'll use the method of first installing the current version of macOS on the external drive, booting into it, and then upgrading via Software Update.

As a footnote, initial testing with Tahoe 26.0 looks positive for my particular setup. That said, I don't find that any of the new Tahoe features are "must haves". I'll probably stick with Sequoia for a while longer.

Thanks for this. At one point, I had installed a trial version of Parallels on an old Intel Mac mini. I found that certain functions/applications didn't work well (if I recall correctly, an audio editor didn't work properly).

I can certainly empathize with not using external drives for the OS. I've spent hours recently and in the past (I'm thinking about Monterey 12.3) trouble-shooting installation issues. On the other hand, internal storage is relatively expensive. I chose a 512GB internal SSD and coupled in with a 2TB Samsung T7 and an older 500GB Samsung T5. This configuration works very well on my M2 Mac mini (2023) with 16GB of memory for my needs.

Another reason for wanting to test the new OS on an external drive is avoid potential surprises. My spouse uses her M4 Mac mini for teaching. She gets rather upset when I break something that she depends on. It's hard for her to appreciate "future" benefits when she just wants to get her work done.

- Pie Lover

Thanks. Depends what you mean by "supported", I suppose, but you definitely have a point. For example, Image Playground will inform the user that it can't be run from macOS installed on an external drive. Of course, there could be other instances of such behaviour that I haven't come across.

Your post reminds me that I should run etresoft on Tahoe. Thanks again for creating this very useful tool.

- Pie Lover

P.S. I actually did contact Apple support for the misinterpreted volume encryption issue. I'm not holding my breath for a response though. :-)