Debian Bullseye, KDE hangs - where to look for errors?

I have been having major problems w/ one of my systems, I attempted to both upgrade the (stuffed) 500gb spinning hard drive to a 1Tb SSD, and go from Debian 10 (Buster) to 11 (Bullseye) using KDE as my X environment…

After a bunch of assorted problems, I ended up doing a complete install from scratch to the SSD, and then copying all of the NON-hidden files from my /home on the old drive to the new one. (I’m willing to re-create any config files and so on, I just don’t want to lose my data…)

The only programs I’ve installed so far that are not in the standard install are Synaptic and Tor.

I am having problems with KDE randomly hanging in a variety of inconsistent and annoying ways. When it gets hung the mouse cursor moves around, but might or might not let me switch windows. I might or might not be able to use to switch out of KDE to one of the other tty’s… If any of these things do work, it may only be after a long delay…

It seems like Firefox MIGHT be the problem, but it isn’t at all clear that it is. I’ve done the Mozilla suggested troubleshooting procedures and they haven’t shown any obvious problems.

I’ve heard suggestions of looking at /var/log, to see if there are any messages there that might be useful in troubleshooting, but it isn’t clear which one of the MANY files in that directory is likely to be useful… Any suggestions?


Would you mind providing the version of KDE you are using?

It would also help, if you provided more system information.

Run all commands as the root user.

inxi -Fxmz
dmesg --time-format iso > dmesg_$(date +"%Y%m%d%H%M%S").log
dmesg --time-format iso -l err,crit,alert,emerg > dmesg-err_$(date +"%Y%m%d%H%M%S").log

You can upload the two log files. If it isn’t possible to upload to this forum, consider using a cloud service or something like the following.

From KDE “Info Center”
Operating System: Debian GNU/Linux 11
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2
Kernel Version: 5.10.0-17-amd64
OS Type: 64-bit
Processors: 12 × Intel® Core™ i7-3930K CPU @ 3.20GHz
Memory: 47.0 GiB of RAM
Graphics Processor: NV92

I thought it had 48GB RAM, (4x 4GB sticks, + 4X 8GB sticks)
It is an early generation I7 CPU on an Intel DX79SR Mobo
SATA 1 - /dev/sda is the 1TB SSD with everything but /swap on it.
SATA 2 - /dev/sdb is a 400GB spinning disk, w/ W10 in a small partition (which I have not yet tried to set up for dual boot) and a 50GB swap partition - not that I’ve ever seen the system use swap, given how much RAM it has…
SATA 3 is the optical drive (HP CD-RW/DVD+/-RW DL Drive)
SATA 4 -/dev/sdc is a 500GB spinner w/ the old install on it - the former /dev/sda
SATA 5 - /dev/sdd is a mostly unused 400GB spinner
SATA 6 - /dev/sde is a mostly unused 250GB spinner

root@fancy-box:/# inxi -Fxmz
bash: inxi: command not found

log files are at

for about the next 24 hours or so…

Hope this helps…


This is an extremely ancient version of KDE Plasma.

I already suspected this, because you are using Debian Stable, i.e. an operating system based on extremely ancient packages.

You need to install the newest KDE Plasma version.

@nevj Debian Stable is recent enough, right?

Interesting - I thought Bullseye is the latest stable - and supposedly I’ve updated it from the 11.4.0 install DVD to the latest it has…

Will investigate what it takes to upgrade, hopefully without breaking things worse than they already are…

You did nothing wrong. The problem is, that the latest Debian offers is already very old, sometimes extremely old.

Debian’s philosophy is based on the idea that yesterday’s software is more stable than today’s version of it.

Sometimes, that might be the case, but in the case of KDE Plasma, it could not be more wrong.
KDE Plasma has received tons of updates, improvements and bug fixes in the past couple years, that your version is pretty much ancient compared to the currently newest version.

It wouldn’t make any sense trying to fix your issues with KDE, because they are most likely fixed already anyway, in the newest version.

You won’t get very far with Debian Stable in this matter. Though, I’m not sure. You can try.

This does not help … just info I saw at Wikipedia about KDE.
Rel 5.20 came out Oct 2020 – no longer supported.
Rel 5.24 still supported.
Rel 5.25 latest release June 2022.

Why look at third party sources, when first party ones are readily available?

Just did a search and click on one of the items that came up.
Your link will provide way more info.

easyt50 did give some useful info, in that he gave some history w/ dates / status on 5.20 (which I didn’t find on the site…)

Their distribution wiki page says that Debian testing and unstable have more recent versions, so it looks like I possibly need to figure out how to enable selectively updating from those without moving everything (I mostly don’t need bleeding edge, and like stability…)

Ironically, looking at the link from Akito, I don’t really see anything in 5.25.5 that I actually want… I hate touchscreens with a passion (I use a flip-phone because it has REAL buttons and mostly ONLY makes phone calls…), and don’t see any need for more colors… I also don’t use (and turn off as much as I can) ‘activities’ and multiple desktops - I actually use very little of what is ‘new’ in KDE since around KDE 2 or 3…

So I’d be happy w/ 5.20 if I could just get it to be stable…


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Such business can easily become very problematic. Not recommended.

This is just an announcement. Announcements are for the shiniest and most glaring improvements.
Announcements don’t show the 100s of contributions which probably fixed all the bugs you experienced.

That’s why designers decide what is needed and what is not.

Most of the time, when people say something like this, it became obvious, that people don’t notice most of the time what features they use. Most of the time, they won’t even notice if a bug is fixed.

Ironically, they would start noticing very quickly, once the support for that particular feature would be dropped… :smiley:

The randon hanging experienced by @ex-Gooserider is not KDE related, it is Firefox related. I experience the same thing when I use firefox either in Debian or in Void, and with any DTE… kde, Gnome or Xfce.

So updating KDE in Debian would , I think, not solve the problem. And it is not a good idea to undermine Debian Stable by adding versions not covered by the package system.
My solution is to use Waterfox instead of firefox… … It can be installed outside the package system, and therefore does not interfere with Debian package system… Waterfox looks identical to firefox… you would not notice the difference. You can have Waterfox and Firefox both installed. They will not interfere.

If you use Debian, you are committed to the stable, out of date, philosophy. So dont undermine it by trying to add more recent package versions. If you really want the most recent of everything, choose a rolling release distro, but be prepared for some occasional instability.

If Firefox is causing such huge issues, then it’s most likely already fixed in a non-ancient version. So, the same logic applies to any software on that Debian Stable. I just picked on KDE first, because this is the most glaring piece of software with an ancient version on that system.

What if it is needed, because a newer version has something the user absolutely needs? Don’t Linux folks say always something like “you can do anything on Linux”? :wink:

So, you are admitting that Linux is too stupid for one of the most popular programs on earth. Great. You have to use some derivative of it, otherwise Linux will stop working. What an amazing operating system! :smiley:


Wasn’t Linux all about freedumb and shit? If you are going to follow an operating system’s unwritten rules, anyway, then you might as well just use Windows and have no trouble in the first place. Just follow Window’s rules, by not horsing around too much and your system will work perfectly.

If I understood correctly, he wants most things stable, but some programs should be more recent, due to their lack of bug fixes in earlier versions.
Freedumb Debian Stable Linux can’t handle that, is what you are saying.

I don’t use any Linux GUI at this moment, but my friend does use Linux GUI systems since many years, exclusively.

According to his experience, which I really appreciate, Arch Linux is the most stable distribution he ever encountered. The problem with Ubuntu, etc. is that by trying to be “stable” they don’t deliver recent enough versions of programs. So, you are always forced to wait for critical bug fixes. Additionally, you have to wait even longer on those fixed release distributions.
On Arch Linux, you usually get a fix within a week or less, if there is anything to fix.
Most of the time, there is nothing to fix, because everything works, since it’s not on some stone old version.

Well actually it is the more recent firefox within Debian and other Linuxes , that has the problem… It is Firefox that is broken, not Linux.
In this case the older version of the package would be better.

I agree @Akito , its a mess. Choosing Debian stable is supposed to avoid most of these sort of issues. Changing distros is probably not a fix. It is in all 4 distros that I run… Debian, Devuan, Solus, Void. It must come with a security update, otherwise why would Debian and Devuan be updating firefox?

When it first happened to me I thouhpght I had hardware probldms with mouse. Then I observed it only hapoened with firefix running, and not with waterfix running. So I just did everything with waterfox… instant fix. I was lucky, I already had waterfox installed. It is not hard to install.
There is a document

I can disprove that right now. I use Firefox every single day on Windows and haven’t experienced a huge issue since like 5 years, at least.

Therefore, yes, Linux is broken. Firefox is fine.

Don’t know. The stable fixed releases are good for doing nothing outside of server purposes. That’s what I know.
For servers these distributions are fine, but for end-users I just see them being too ancient, all the time.

Windows firefox is a different firefox… all its system calls will be different.

Firefox for Linux is broken, not Linux.

So, you are saying, making a program for Linux makes it already broken, because Linux is broken and making the same shit for Windows works, because Windows just works?

Finally, we agree. :smiley:

If Firefox for Linux is broken, but the same shit works great on Windows, then Linux is broken, because that is the only variable that changed. Everything else stayed the same. It’s literally the same program. No difference.

No, it is the firefox interface to Linux that is broken.
That is the responsijility of firefox, not Linux.
Linux provides all the needed system calls, other programs use these calls without problem, firefox did not use the calls properly.

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I MAY have solved it - :grinning: I’ve now been up and running for several hours w/o any problems…

Given Nevj’s comment about the problem being Firefox rather than KDE, I went through the Mozilla troubleshooting stuff again…

What seems to have solved it is in the “Performance” section of Settings, there is a checked box for “Use recommended performance settings”… Unchecking the box brings up a second checked box for “Use hardware acceleration when available” Unchecking that box seems to have solved the problem…

I would have thought that an I7 CPU (even an old one) would support hardware acceleration, but apparently not… Doesn’t seem to be a big deal, as I seem to be more bottleknecked by connection speed than anything else…