This has nothing to do with VirtualBox. Other than the fact that VirtualBox caused the UUID to change when attaching to a new system. The same thing would most likely happen if this were a physical disk moved to another physical system. This is a normal Linux mount error when using UUIDs.
UUIDs can change for a number of reasons, installing to another partition on the same drive, cloning the disk, etc..
The easiest 3 fixes:
- attach and boot to a rescue live-cd iso on the broken system (the newly created virtual client).
- Mount root
- cat /etc/fstab - look for the UUID for / or the mount point causing the error.
- reset the drives UUID - tune2fs /dev/sdXX -U UUID
or
- attach and boot to a rescue live-cd iso on the broken system
- Mount root
- cat /etc/fstab - determine the mount point causing the error.
- determine current UUID - ls -l /dev/disk/by-uuid
- edit fstab to the new current UUID
or
- attach and boot to a rescue live-cd iso on the broken system
- Mount root
- edit /etc/fstab - determine the mount point causing the error, rewrite into the old format /dev/sdXX (or /dev/hdXX if still using IDE on older systems)
Tinycore and Puppy Linux make great small rescue cds with web browsing support. Use Knoppix or Trinity Rescue Kit for more features.
You can always attach the "broken" system's disk to another working virtual as a secondary disk to do the above edits.