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UPDATE [AM 17 Sept. 2025]: Issue has been solved!
(I might at some point post the entire process with screenshots and stuff… But anyway,)
In short;
After @Auth suggested to just copy the contents of the inaccessible user’s homedir to a new user, I logged in with tempuser and fast recalled that said homedir was similarly inaccessible as such, as I had selected the option to encrypt home directory during installation, and thus the files within were to other users unreachable without first decrypting them.
I followed @just_another_person’s [advice/instructions] until they stopped replying, then managed to successfully mount the home directory after running through the other steps of the guide they referenced ([see:34365607/19080549,34365607/19187230]). I then realised that maybe I could just reverse all the steps I had taken since the user was last accessible, ([see:34365607/19187230]) and regain full access to the user, so I formulated a list of commands to reverse the steps, ([see:34365607/19233599]) checked for flaws, couldn’t really find any, and just tried running the commands.
Anyway, it worked, and I can now log in to the user again and access all the files!
Much thanks to everyone who commented, and thanks again to @Auth, @just_another_person, @Wolf_Munroe, @Fizz and again (again) to @just_another_person for continuing to reply for so long!
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Hi fediverse,
I’m hoping someone can give me some advice on an issue that means I can’t access the main user account on my Linux Mint (Cinnamon) operating system.
Context:
I’m using a dual boot setup of windows and mint on my laptop. I use mint (or used to, when I could access my user) for pretty much anything that doesn’t require things* only my windows instance has. (*things such as support for video games that support windows but not linux, for example)
When creating my main user account, I made a mistake in the username. It was irritating enough for me to want to change it, and as doing so seemed like it should have been fine, I settled upon three guides and ended up (mostly?) just following this one:
https://www.linuxuprising.com/2019/04/how-to-change-username-on-ubuntu-debian.html

I cant remember all of what happened anymore, but I have the following screenshots, along with the stuff I do remember.
(note: red blocks represent the new username, blue blocks represent the old username)

At the used-by-process error, I first tried following the guide precisely, then hoped that “PID” was Process ID, and that the guide expected me to put the ID that usermod stated after “PID”, and tried doing that.
Idk if that fvcked something up…
Then I guess I fixed that somehow, idk if I did so by restarting and logging in only as tempuser, or if I had already done that and fixed it some other way.
Anyway I meant to run each line of the command separately to avoid stuff going wrong, but accidentally did both at once. I hoped it’d be fine anyway.
Then stuff happened I guess.
Anyway,
I cant remember much more but I know that I tried to log back in as my main user account and I found out that:
- The username had been successfully changed.
- I could not log into my main user account.
Inputting the correct username and password was successful, and acted like it was logging me in as usual. Then after the usual black screen, it just throws me back to the login window.
This still happens.
I ran some web searches, followed some advice. All that I could find of relevance was mostly just people saying to check how much disk space you have left - and to not keep timeshift snapshots on the same drive as your OS.
(this is one such post, which I’m pretty sure is the only one I found that I definitely recognise from the previous searching: https://www.reddit.com/r/linuxmint/comments/15revgg/cant_stay_logged_in_keeps_going_back_to_login/)
I did ctrl-alt-f1 and ran df -h, and deleted most of the timeshift snapshots I had (I think I had maybe 6 and deleted 4 or 5).
Here’s the output of df -h that I think is from after I deleted the timeshifts:

Idk what to do, hope someone can advise.
(TL;DR: tried to change username on mint, now whenever I try to log in to the user it throws me back to the login window after the usual black screen. Hope this suffices for a summary…)
[(Edit [AM 06 Sept. 2025]: fixed typos, phrasing…)]
[(Edit [AM 17 Sept. 2025]: UPDATE [SOLVED])]


Needs to be an existing directory
I know, I created the folder “oldhome-mountpoint” in “/home/newuser/oldhome-backup”, then copied the path to that and used it as the specified mount point in the command, or at least I thought I did. I’ll double check it again
I still don’t know what to do at this point in the process, If you could get back to me at some point soon that’d be neat.
I looked for answers on the internet and haven’t found much of use, but I also asked a few LLMs and the responses all suggest that this choice is expected behavior for this process, though again, said choice does not appear in the guide, so idk.
As I said, both directories seem to exist.
(Again, what should I do?)
Then create an empty directory and use that as the last argument.
Theast argument just needs to any directory that exists and is empty. It’s simply a place the contents of the mount will be available for interaction after you run the mount command.
Could you at some point reply to this comment pls?: (34365607/18915085)
You’re pretty lost in this chain. We offer paid remote help if you want that. Feel free to DM me.
I can’t really pay, and I feel like using dms for this kind of stuff kinda just denies others access to the information provided/discussed. (If what you say could be useful to me, it could also be useful to someone else)
Could you just try to help me progress further toward sorting this out?
Again; The directory provided as the last argument in the command seems definitely to exist. Should I select an option when the two options are provided, and if so, is the first option preferable?
If you don’t quite know how I should proceed, or otherwise can’t provide further help, that’s also fine, but please let me know either way. (Also idk exactly what “We offer paid remote help if you want that” means, but if you don’t have the time/wherewithal/etc to provide further help without pay or whatever, the same applies)
If you’re getting an error, please provide it. If it’s just saying you’re missing the final argument as the mount point, you’re doing something wrong. The mount command at its base works like this:
mount [sometargethere] [someemptydirectory]I just need to know what to do at this stage (the stage described in [34365607/18807477]):
There’s no error, I just don’t know what to do when presented with these two options. Is this expected behavior? As I said in [34365607/18807477], this dialogue (the choice between passphrase and tspi) doesn’t appear in the “HOWTO: Recover files from encrypted ecryptfs home directory” guide, so I just wanted to check that said dialogue was what was supposed to happen, and if so which option I should select.
There are more details and stuff on this in my previous comments, I’ll quote them below in chronological order so they’re all in one place.
Relevant comments in this chain/thread (chronological order):
Hir 1 and enter the passphrase for the volume. Try whatever the previous login password was, or if you know the right passphrase, enter that. The value is what YOU set when you installed the first time.
Since it has taken two comments to get through to you the past few times, here’s a second comment.
Please just reply to the first one at some point… It is my reply to this. - i.e. my reply to the comment I am replying to with this comment. (34365607/19002981 - https://lemmy.world/post/34365607/19002981 < the first one)