Ubuntu 16.04 and virtualBox 6.0.4 losing state

[yodellingTom]

I have upgraded my virtualbox from v5.1.22 to v6.0.4 and I am using Ubuntu16.04 guest.
I have also installed the virtal box extension pack for v6.0.4

Since I've upgraded I have noticed that changes I make within my ubuntu environment are not always guaranteed to be retained if I "power off" virtualbox and then relaunch it.
The latest manifestation occurred this morning.

I am using git as a source repository.
- Last night I created a local branch within ubuntu16.04.
- I then pushed this branch up to the remote repository
- I checked the remote repository to ensure that was done successfully
- I then "powered off" virtual box
- This morning i launched ubuntu16.04 to continue working in my local branch
- made changes and was ready to push but got this message "Your branch is based on 'origin/card-32851', but the upstream is gone."

I have checked the remote git repository and my branch is still there.
I can only assume that whatever was held locally within my Ubuntu guest to maintain the link to the remote branch in git has been lost.

Has anyone else experienced similar issues?
Is there a fix available?

[mpack]

Usually this means that you are running a live CD boot of Ubuntu, but without solid info this can only be a guess.

So please post a VM log file. With the VM fully shut down, right click and "Show Log" in the GUI, save "VBox.log" (no other file) to a zip, and attach the zip here.

[yodellingTom]

Thanks for replying.

I've attached the log as requested

[mpack]

Apart from having the wrong Guest Additions installed (i.e. GAs from the Ubuntu fork), I don't see anything wrong in the log. You are not suspending/restoring, and you are not booting from a live CD. So unless you've configured the immutable drive option in the VM settings (storage), then I don't see how this can be a VirtualBox problem.

The only memory VirtualBox has of what should be on your virtual disk - is what is now on your virtual disk. Unless you have enable some kind of differencing storage scheme (snapshots, immutable drive, linked clones) then it isn't possible for VirtualBox to restore an earlier state, because it has no memory of that state.

If you aren't using a differencing scheme then your problem must be internal to the guest.

Looking again at your log I see that a differencing image is indeed being used :-

00:00:02.678921 File system of 'C:\Users\Tom.McCoy\VirtualBox VMs\MainUbuntu\Snapshots/{019fe1ea-1ef5-4620-9b9c-2b2521dbfd85}.vdi' is ntfs

But I can't tell if that's a snapshot or an immutable drive. Snapshots should not (and AFAIK, don't) behave in the way you describe: you have to explicitly revert them to earlier states. If the snapshot file was readonly and hence did not get updated then there would be an error message from VirtualBox.

[yodellingTom]

Thanks for your help