The latest 'VirtualBox' upgrade (in Bullseye) to 6.1.34 appears to be broken. I don't know about the Buster based versions (I think that's lower).
So either wait for a newer upgrade or downgrade to 6.1.32 to have it working.
A temporary "work-around" in some cases is to replace '/usr/lib/virtualbox/VBoxDDR0.r0' with the one from the previous version ..... 
Don't do that.
Do an 'apr virtualbox', then download: https://download.virtualbox.org/virtualbox/6.1.34/virtualbox-6.1_6.1.34-150636.1~Debian~bullseye_amd64.deb
which is a newer 'fixed' version and install that.
Is it that DKMS kernel module thing? I'm running into that.
Nevermind, that was probably me not having the kernel headers installed when I upgraded to Bullseye. (Can't remember - did you put that in your howto?)
dkms is giving strange error messages when I upgrade my kernel to 5.16 but isn't necessarily restricted to virtualbox.
I don't know which Elive base you're running but Buster hasn't reached 6.1.34 yet, I believe.
Bullseye and I regret it. 
List of my problems
- Nvidia drivers fucked up and the installer fails to compile them (!!)
- VirtualBox no longer working
- Some packages I need don't have Bullseye equivalents so I have to messily use the Buster ones. It works, for now...
I'll probably have to reinstall sometime. I just don't trust the "auto migration" 
Don't !!!!
The next versions will be Bullseye .... it's inevitable.
I was one of the first to bite the bullit and ..... I'm actually glad I did. 
Yeah, that'll only work if you keep track of everything you've installed in the meantime, that's my downer too.
So I just do a lot of 'apug' and find a newer kernel every now and then..... i.e a 'sort of' rolling release.
I know, but right now I can't even find kernel headers in the repos.
There's none that I can find for 5.10 bpo5, and there are no newer ones with bpo5. I'm not sure if I can install a different BPO, if I can that'll fix many of my problems.
The bpo version isn't that important, just take the highest.
What I do for my machine:
apse linux-image-5.1 |grep bpo. |grep amd64
and pick the highest..... currently 5.16.0 bpo4
and install the image and headers.
Oh, I thought the bpo was important.
Installing the newest kernel. 
Well you know ..... you can always fallback on the previous one, on boot ehh?
Rebooting my system is a pain.
Um...?
Error! Bad return status for module build on kernel: 5.16.0-0.bpo.4-amd64 (x86_64)
Consult /var/lib/dkms/nvidia-current/460.91.03/build/make.log for more information.
Kernel preparation unnecessary for this kernel. Skipping...
Building module:
cleaning build area...
make -j12 KERNELRELEASE=5.16.0-0.bpo.4-amd64...(bad exit status: 2)
Error! Bad return status for module build on kernel: 5.16.0-0.bpo.4-amd64 (x86_64)
Consult /var/lib/dkms/vhba/20210418/build/make.log for more information.
Error! The /var/lib/dkms/wireguard/1.0.20210219/5.16.0-0.bpo.4-amd64/x86_64/dkms.conf for module wireguard includes a BUILD_EXCLUSIVE directive which
does not match this kernel/arch. This indicates that it should not be built.
I'll probably move these messages to another thread (or delete them) later.
why? Just a matter of jumping into TTY1 with 'ctrl+alt+F1' and then hitting 'ctrl+alt+del+ on my machine.
I just had the same message on installing.
The message on the wrong 'arch' is strange ..... must be something wrong there. 
It's not the reboot that's the problem. It's that I'm constantly running non-resumable long-running processes.
Most of those are X11 related or have to do with disk encryption.
On TTY1 you can see the messages and after a while just force a shutdown by pulling the plug.
I just reboot on 3.16 but that kills off virtualbox. Even if I reboot into 5.14 it wont show anymore although it clearly is running. 
That's not what I mean by longrunning non-resumable processes.
I mean processes I start.
OK, I can get VirtualBox to run on both kernels now after re-installing the testing 6.1.34 from Oracle.
I did have to wait a while a while for dkms to get it's act together.
It shows on 'top' as 'cc1' command.
Guess I'll stay on 5.16 now.
