Question
I stumbled upon a peculiar situation in Ubuntu Desktop 22.04.4: If the NetworkManager service is enabled, the PC boots to a gray-colored blank screen, like when the display monitor is off. I would like to ask for help fixing that.
Context
I installed and removed a couple of snap packages, one of them being a VPN client. (I probably did more than that in the last boot, where the system was properly working.) After restarting the PC, it boots to a blank screen.
The default GUI and the X11 windowing system are being used. A single display is attached to the NVIDIA card. The iGPU multi-monitor is enabled in the UEFI. This whole configuration was there for a while and the system worked in a stable manner.
More details of the problem and my troubleshooting efforts are available in the following section.
What I Have Tried
When
NetworkManageris enabled:GDM is configured to automatically log in to my default account. On the blank screen, running
Ctrl+Alt+Tand typingsudo rebootfollowed by entering the password of the account and pressingenter/returndoes not work. I think the desktop environment is not loaded at all.If I switch to another GUI using
Ctrl+Alt+F1, I will see a logo of a computer with crossed-out eyes and a down-turned mouth saying:
Oh no! Something has gone wrong.
A problem has occured and the system can't recover.
Please log out and try again.
, along with a "Log Out" button.
I can successfully switch to a new CLI using
Ctrl+Alt+F3. Restartinggdm3does not resolve the concern of the GUI not being loaded.If I press
Alt+SysRq+Ethe blank screen turns into a black screen for a moment, and then the desktop will be loaded. Here, I face two difficulties: First, the network interfaces (Wi-Fi and Ethernet) are not present in the GUI. The GUI settings window notes that I should enable theNetworkManagerservice. Second, the Windscribe app (which has been installed for a long time) fails to open and demands to be restarted.Restarting
NetworkManagerfixes the problem of interfaces not being available. However, Windscribe error persists no matter how many times I restart it and regardless of whether or notNetworkManageris restarted.
When
NetworkManageris disabled:In this case, the PC successfully boots to the desktop environment.
Here, the problem is that I have to start
NetworkManagermanually:sudo systemctl start NetworkManagerInterfaces, and Windscribe work fine.
I can successfully switch to another GUI.
Taking a quick look at
syslogandNetworkManagerlogs, nothing jumped out as particularly significant. To be honest, I'm unclear about what exactly I'm supposed to look for.
Related (seemingly not duplicate) Questions:
Diagnostics
Disabling automatic login (suggested by @eyoung100):
Action: I disabled
NetworkManager(NM); rebooted; disabled automatic login via settings GUI, ensuredAutomaticLoginEnable=Falsein/etc/gdm3/custom.conf, enabled NM again; and rebooted to see the effect.Result: Login screen is visible. After logging in, only a blank screen is seen; changing GUI using
Ctrl+Alt+F1results in the same exact result; usingAlt+SysRq+Emakes the screen black, and then gray (like the display is off) again. A way to log in is to first end all apps using a system request, then log in via current or the other GUI, both result in network interfaces and Windscribe not working.Result with enabled NM: The result is exactly the same as before even if I disable the NM again and reboot, that is to say, I cannot log in regardless of the status of NM when automatic login is disabled.