A couple of days ago I had a problem with VirtualBox, I couldn’t start one of my VMs because it was displaying an error message saying: “VERR_SUPLIB_OWNER_NOT_ROOT” Searching on the internet I found this bug. and they suggested to run: chown -R root:root /usr/lib/virtualbox chmod 4711 /usr/lib/virtualbox/VirtualBox This didn’t fix my issue, so I started to dig deeply into the issue and I found a log file on ~/.VirtualBox/Machines/VM/Logs/VBox.log with the following message: 00:00:00.448 pdmR3LoadR0U: pszName=”VMMR0.r0″ rc=VERR_SUPLIB_OWNER_NOT_ROOT szErr=”The owner is not root: ‘/usr'” I took a quick look at /usr permissions and I found that for some weird reason, it had uid:gid 500:500 # ls -ld /usr drwxrwxr-x. 13 500 500 4096 Aug 3 2006 /usr Solution: chown root:root /usrHace[…]