After upgrade of dkms (2.8.5-1 -> 2.8.6-1), it failed to erase the old directory entries each time a new module was built. In my case with virtualbox, I ended up with:
drwxr-xr-x 4 root root 4096 Sep 3 16:00 6.1.24_non_OSE drwxr-xr-x 6 root root 4096 Sep 10 10:42 6.1.26_non_OSE drwxr-xr-x 4 root root 4096 Sep 11 02:29 6.1.27_non_OSE
The old entries would cause dkms status to fail with:
Error! Could not locate dkms.conf file. File: /var/lib/dkms/vboxhost/6.1.24_non_OSE/source/dkms.conf does not exist.
I had to manually remove the 6.1.24_non_OSE and 6.1.26_non_OSE. What happened and what should I check to fix this?