SDDM will not log in to wayland session, will to X11 session

Help
1

Suddenly tonight after a normal shutdown, when I restarted the machine SDDM would not log in, it just kept returning to the login. I dropped to a recovery tty and tried manually starting wayland, and got “Detected locale “C” with character endoding “ANSI_X3.4-1968”, which is not UTF-8”. I tried setting the locale, but the problem persisted. I finally tried logging in to an X11 session, and that worked. SDDM will log in to X11, but not wayland. I’ve been searching the internet for a fix, but haven’t found anything exactly like what I’m experiencing.

I’m running Debian Sid on a Thinkpad T480, and have been for a long time, without issues. I do an update daily on most days, and I haven’t shut the laptop down for a few days.

2

I restored a Timeshift backup from ~10 days ago, ran an update, and now I can log in to a wayland session again. I have no idea exactly what the cause of the issue was. I hesitate to mark it as solved, because I want to make sure things stay working for awhile first.

3

I think this message is probably unrelated to your problem. I see it on my machine too, but I have no actual problem with SDDM on Wayland.