virtualbox.org

hello
I have VM using differencing disk image. I have no idea why it uses differencing image since there is no snapshots for this machine (now).
I had two snapshots previoously but I deleted them, so now I have only one "current state".
But in virtual media manager I see that this machine is connected to differencing image (of 6GB). No other machines are connected
to this disk at all. My questions are:
How to interpret such situation?
and:
What to do to merge this differencing image to the main one.

best regards for all !

Ok, now I know the reason and solved the puzzle of merging.
Reason: sharing disk between machines. VBox creates individual differencing images for all machines and it is not reprezented in snapshot tree and there is no normal way to merge images.

Solution: familize with vm configuration file and tweak manually to create snapshot, and then delete it (and merge) on gui

I had the same problem but was not willing to get familiar with the configuration file so I went a different way:
I made a clone of the existing harddisk by

vboxmanage clonehd original.vdi cloned.vdi

The cloned HD was a copy of the original HD merged with the hidden snapshot.
After that I attached the cloned HD to the Virtual-Box machine (and tested it).
In the manager for virtual media I could now delete the snapshot and the original HD.

Cloning the difference image to create the basis for an independant VM is IMHO the correct solution. The earlier suggestion would modify the base image being shared by several VMs, and hence sounds like a pretty good way to corrupt the other VMs.