Akmods is the Fedora/Red Hat way of managing kernel modules. In Ubuntu, this is dkms. If you’re like me and force reboot shortly after performing an update, then you might have not given akmods enough time to compile any extra kernel modules (for example: Nvidia). This meant that I had to boot into an older kernel to try to fix the problem….

Once in the older kernel, you can check the kernel versions by:

ls /usr/src/kernels/

Then select the kernel which you failed to build and run:

sudo akmods --kernels 5.15.18-200.fc35.x86_64

to trigger the rebuild.

Though the better solution is to avoid this problem to begin with. If you reboot not as root, then systemd will check to see if any process is inhibiting the poweroff. If that’s the case, wait patiently and don’t type sudo reboot.