VirtualBox will delete VM settings at startup if DVDImages with conflicting UUIDs exist in VM MediaRegistry -> duplicate of #17908

[Carlos D.]

This issue frequently deletes a large part of VM settings (namely Display, Storage, Network, USB, Shared Folders) if multiple VMs have conflicting UUIDs of the same DVDImage in their MediaRegistry blocks. The conflicting UUIDs seem to be introduced by BOINC tasks (Distributed Computing using VirtualBox for some projects) that are created and configured automatically. Possibly they don't register their mounted VBOXGuestAdditions.iso correctly, and any later mounting in a regular VM creates a conflicting UUID.

For my test I used a fresh VBox config and created three VMs from scratch: Test1, Test2, Test3. All are created with the default template and settings the Windows VBox offers (Windows 7, default RAM, HDD size etc). Then, for all three VMs, I loaded the VBOXGuestAdditions.iso to their virtual DVD drive, then ejected it immediately. That created the entry in their MediaRegistry.

      <DVDImages>
        <Image uuid="{8c2aa2b9-4628-401d-88dc-707d8825017f}" location="C:/Program Files/Oracle/VirtualBox/VBoxGuestAdditions.iso"/>
      </DVDImages>

All three have the same UUID for the ISO, so anything is fine. Only for quickly recreating the issue, I now manually modified the UUID of the Test1 VM to another, valid one. I know that it should never happen, but unfortunately it does.

      <DVDImages>
        <Image uuid="{707d8825-401d-88dc-4628-017f8c2aa2b9}" location="C:/Program Files/Oracle/VirtualBox/VBoxGuestAdditions.iso"/>
      </DVDImages>

The next start of VirtualBox deleted the settings of Test2 and Test3.

Attached are some screenshots, the vbox files and the VBoxSVC.log.

Notes:

1. There is no VM VBox.log, since none of the VMs are ever started.
2. VBoxGuestAdditions.iso is only an example, every ISO works.
3. The VMs having Harddisks attached is a requirement. Without Harddisks the VMs become inaccessible (which I think is correct behavior).
4. All VMs and config files are on local HDDs and accessible at all times. No configs are ever moved.
5. While the VirtualBox.xml file has a MediaRegistry block, nothing was ever registered there.

As for the solution, while the correct solution would be to display the "Inaccessible" message for conflicting VMs, that would probably break BOINC tasks, frequently. So, would it be possible to simply update the wrong UUIDs to the right one, if the complete path to the ISO is the same? Because it is the very same ISO, then.

I hope that's enough information to recreate.

Backlink to original forum topic: ​https://forums.virtualbox.org/viewtopic.php?f=6&t=77399

[Carlos D.]

Original Test1.vbox

[Carlos D.]

Original config screenshot. All three VMs are identical.

[Carlos D.]

Test1.vbox with conflicting, but valid UUID inserted.

[Carlos D.]

Test2.vbox after the bug impact. Test3 is the same, Test1 is unharmed.

[Carlos D.]

Test2 screenshot after bug impact. As you see most settings are gone.

[Carlos D.]

VBoxSvc.log from startup.

[Michael Thayer]

Marking a duplicate of #17908, as pointed out there by Carlos.