William Morder composed on 2026-08-03 07:43 (UTC-0700):
This might be totally irrelevant, and if so, please ignore me. However, I haven't noticed anybody mentioning tdm-trinity.
Make sure that tdm-trinity is installed, and it would be a good idea to run this command:
sudo dpkg-reconfigure tdm-trinity tde-tdebase
Mainly you want to reconfigure tdm-trinity, so that you can use that are your display manager.
As his screenshots show he's obviously in a TDE session, I chose to not digress from the problem accessing his data partition, assuming LightDM or whatever got installed with Cinnamon is up to the task of starting TDE by opening /usr/share/xsessions/trinity.desktop. Switching DM can wait.
Also, there is no shame in using a GUI to get there. The method that Felix uses is a little beyond my own capabilities at present, mainly because I am limited to just one machine; so if anything goes wrong, I can't get online to get help, or to communicate with the TDE mailing list.
I stick to the underlying basics as much as practical. Different DEs provide different tools for various admin tasks. I have no idea what Cinnamon offers in distinction to anything else, much less how to use it.
Just because I have lots of PCs and installed distros doesn't mean I have every possible combination, as even if I cared to, I could never come close, much less be familiar with so many different tools. Chris started with what he started with, so I try to help without destroying what he has that does work in the process, while hoping he learns something from tasks I present, and can be satisfied with whatever results.
I haven't mentioned anything about ACLs. I don't use them, so am unfamiliar with how they work and how to control them, but they could be involved with how Cinnamon setup his data partition, and could be interfering with my attempts to help.
Perhaps it would help Chris to peruse an overview of permissions and ownerships, e.g. from: https://www.linuxjournal.com/content/mastering-linux-file-permissions-and-ownership It has a cursory overview of ACLs.