[Post-Install] Error Su returned with an error after fresh install

[cevaude]

Hi all,

On Monday I did a fresh install of Kubuntu 25.10 on my PC and from time to time I get the following error popup, sometimes even multiple times in quick succession:
https://ibb.co/gCXMfX6 (embedding or attaching the image somehow does not work).

This morning I did a new fresh install with the hope to fix it by that, however this did not improve anything.

I searched the web and found not much, that I could relate to this error. Somewhere I read that this could be due to permissions of the su binary, but they seem to be fine:

ls -l $(which su)
-rwsr-xr-x 1 root root 55832 Sep  6 17:37 /usr/bin/su​

I have no idea where to even begin looking for logs or more detailed error messages and would appreciate any tips. It's a little annoying to get these popups, however as far as I can tell they have no functional impact.

[oshunluvr]

Re. the attachment: you have to have 3 or more posts before you're allowed to add attachments. It gives us moderators a chance to catch the spammers and scammers before they upload anything.

To your issue, I did manage to find this: https://www.reddit.com/r/Kubuntu/com...manager_error/

I'm not seeing this on my 25.10 install, but it's a VM and I rarely use it. From what I see, it may be related to Flatpak being broken in 25.10. Even if it's something else, I suspect it will be fixed soon. If you want to be more proactive, you could file a bug report if one doesn't already exist. Generally, these types of "in your face" issues are caught pretty quickly by the devs.