Sorry for the previous hijacked thread.

The problem is I get error instead of mounting a drive:
Unable to mount this device.
Potential reasons include:
Improper device and/or user privilege level
Corrupt data on storage device
Technical details:
org.freedesktop.UDisks2.Error.NotAuthorizedCanObtain: Not authorized to 
perform operation

I checked my groups. They are: disk, floppy, cdrom, vboxusers, root.
Aren't they enough?