White screen on Kubuntu 25.04 remote

[billdehaan]

I’ve been using NoMachine 8.16.1 on my home network with three Linux machines for about a year without issue. The three machines all ran Linux Mint. Two ran Mint 22.1, one with the Cinnamon desktop and the other with Xfce. The third ran LMDE 6 with Cinammon. All three could NoMachine into the other two without issue.

I recently installed Kubuntu 25.04 on the third machine (it dual boots with LMDE). After installing NoMachine, the machine can connect to other machines, but other machines attempting to connect to Kubuntu get a white screen.

I’ve disabled “use hardware encoding” and “use acceleration for display processing” in the performance tab, restarted the server, cold booted, and there’s been no change.

I know that Kubuntu is using Wayland instead of X11; that’s one of the reasons I wanted to try it out. When I reboot to LMDE 6, I can remote in again without issue.

Since NoMachine works with LMDE on the hardware, it’s pretty clearly a software issue. Given that Kubuntu 25.04 was just released, it could be a new incompatibility (I haven’t tried previous versions of Kubuntu). Whether it’s a Kubuntu/Wayland/KDE issue or a NoMachine issue, I don’t know.

Has anyone else tried connecting to Kubuntu 25.04?
If so, did it work out of the box, or did you need to change some configuration settings?
Does anyone have any recommendations for things I could try, either with NoMachine or with Kubuntu?

I can believe that this could be a Kubuntu/KDE/Wayland setting, but I’m not familiar with Wayland, so I’m not sure what if anything can be configured. I did read a number of “white screen” problems, and they recommended disabling hardware acceleration (which I’ve done). Other than that, I’m not sure what to try next.

Client specifics:  Linux Mint xia 22.1 x86_64, Cinnamon desktop, NoMachine 8.16.1

Server specifics:  Ubuntu 25.04 x86_64, KDE desktop, NoMachine 8.16.1

Both are physical machines (no VMs) and are on the same local 192.168 wired network.

[Britgirl]

Hi, thanks for the detailed report. This looks like a known issue. https://kb.nomachine.com/TR05V11141, specifically with KDE 6 onwards. What KDE version is it?

[billdehaan]

What KDE version is it?

KDE Plasma 6.3 desktop

KDE Gear 24.12.3

Kernel 6.14

FYI, I have since tried it with Tuxedo OS 24.04.01 LTS, with KDE Plasma 6.3.2 desktop, and it works fine. However, Tuxedo OS uses X11, while Kubuntu is using Wayland.

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