Diagnosing white screen issues

[nmus]

Is there a guide for diagnosing whitescreen issues? It seems when something goes wrong with NoMachine, it just shows a white screen with no easy means of diagnosing the issues.

I was hit with this today suddenly without knowing what had changed, and tried multiple combinations of things, updating the client, the server, changing settings, updating the system, rebooting etc. I eventually stumbled onto options to force the video encoding and in combination with some other options that I’m not sure of (since I’m doing it blind) I got something working again.

Web searches proved futile as I found plenty of other issues with the same symptom of white screen but solutions.

The setup was Linux client under XFCE to Windows 10 server.

With the benefit of hindsight, where should I have been looking for solutions? How should I have diagnosed a whitescreen issue?

[Britgirl]

Can we assume you are the latest version which is 8.10? We are not aware of white screen issues as you describe when connecting to Windows or other OSes (you wrote Linux client under XFCE to Windows 10 server). Any white screen issues similar to yours that we encountered in earlier versions have been fixed (you can take a look in the Trouble Reports section of the knowledge base to search them). We are aware of ONE issue connecting to Linux which temporarily shows a white screen and then disconnects with an error, but this does not appear to be your case (it appears when connecting to KDE/Plasma desktop, as well as disconnects with an error). You can find it here:

White screen occurs when connecting to a KDE/Plasma Wayland desktop on Kubuntu
https://kb.nomachine.com/TR07U10921

We’re happy to investigate your issue, but to do that we need to know:

– the Linux distribution/version you’re connecting from
– the graphics card installed on the both sides
– logs from the affected machine (https://kb.nomachine.com/DT07S00243) You can submit them to forum[at]nomachine[dot]com.

[nmus]

Thankyou for all of the information and in particular the information you need and the logs. For now I’ve got it working, and I’m gradually experimenting with options to see if one causes breakage.

During the process I upgraded both the client and server to the latest public versions available at the time of the post, which didn’t change or fix the issue.

Yes, it sounds like it’s a different issue than the one you are aware of. It would remain on a whitescreen for quite some time at least. I saw one disconnect when I left it long enough, but it was certainly not happening all the time.

One interesting thing is that it occurred roughly at the same time that MS introduced animations when changing virtual desktops, and I got it working again after disabling animations to hide that misfeature. There’s a chance that it was related. One thing to check out might be if using animations with virtual desktops causes an issue with NoMachine.

Apart from that, I’d add that both sides use nVidia-based cards.

I’ve got a working setup now so there’s no need to investigate mine specifically, but I hope some of the extra information here helps in any case. For my part, knowing how to get logs and how to approach things if it happens again is useful, thanks for that.

 

[Britgirl]

Thanks for submitting the tip about disabling animations. We’ll certainly check that out.

Some tips if it happens again:

– disable hardware decoding on the device you are connecting from (if you can bring the connection menu up you can do it in the Display settings panel, or do it in the player.cfg file. Follow the instructions here https://kb.nomachine.com/AR07U01202)

–  and/or disable hardware encoding to exclude any problem with drivers (server settings -> server performance -> uncheck “Use hardware encoding”)

– If the server is headless, try to attach a monitor

– If nothing helps, collect logs and send to us https://kb.nomachine.com/DT07S00243

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