So I uninstalled the virrualbox guest additions via sudo purge virtualbox-guest-*
Now it will no longer boot into KDE. If I reinstall virtualbox-guest-x11 it will again boot into KDE.
So I end up the the command prompt telling me to enter username/password.
How can I boot into the GUI without the guest additions?
Perhaps these packages should be installed by default in Non-Qubes-Whonix anyhow then. Just in case upgrading guest additions [or whole Debian] one day goes wrong [in corner cases] it’s better to have a desktop environment at all as opposed to none.
I would agree.
Whereas maybe not the -all package(?). As more packages/drivers might lead to more security risks(?). Only vesa/fbdev as the lowest fallback.
Thanks for the tip with Xorg log, after that the problem/cause became apparent.
EDIT: Just found out, that you had a wiki page about screen resolution without guest additions. Will test this later. (The last part of my post about disabling the kernelmode drivers is still valid though).
Used whonix again today and I found a little problem with the solution of removing all virtualbox-guest-* packages.
When not using the vboxvideo driver you only get 1024x768 as an option. I tried adding new modes to xrandr (800x600 for testing):
cvt 800 600 60
xrandr --newmode <Modeline> (replaced with the real one of course)
xrandr --addmode default 800x600_60.00
xrandr --output default --mode 800x600_60.00
But it failed or nothing happened at all.
So I reverted back to installing guest additions but disabling it via the way described here: Post above.
If you do it like explained on the whonix wiki it will not work and lsmod will still show the drivers being loaded.
At least I hope the drivers are not loaded that way, but I would prefer not having them at all. But if anyone gains root to enable them again this person could also use root to just install them anyway and use a potential exploit for them, so I guess it’s ok that way.