Medium is differencing but not associated with any parent???

Discussions related to using VirtualBox on Mac OS X hosts.
Locked
nuke
Posts: 29
Joined: 10. Nov 2008, 18:51
Primary OS: Mac OS X other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Win7, ClearOS, SnowLep, CAELinux

Medium is differencing but not associated with any parent???

Post by nuke »

Hi!

I just updated to v3.2.8 after shutting down v3.2.6.

When I restarted and wanted to open my XP guest, I get the following error. I don't know what this means or what to do about it. Please help.

Code: Select all

Failed to open a session for the virtual machine WinXP
Medium type of '/Users/Shared/VirtualBox/VDI/{70c...}.vmdk' is differencing but it is not associated with any parent medium in the media registry. 
'/Users/me/Library/VirtualBox/VirtualBox.xml'

Details
Result Code: 
NS_ERROR_FAILURE (0x80004005)
Component: 
Medium
Interface: 
IMedium {1d578f43-5ef1-4415-b556-7592d3ccdc8f}
nuke
Posts: 29
Joined: 10. Nov 2008, 18:51
Primary OS: Mac OS X other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Win7, ClearOS, SnowLep, CAELinux

Re: Medium is differencing but not associated with any parent???

Post by nuke »

Any help would be appreciated in figuring it out.

Also looks like this is a problem with one other user on Linux. See http://forums.virtualbox.org/viewtopic. ... 47#p149947
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Medium is differencing but not associated with any parent???

Post by Perryg »

I don't have a MAC as host at the moment to test this out, sorry. But can you go back to 3.2.6 and see it it still gives this error?
Also do you have snapshots and was the guest shut down or saved when you updated?
nuke
Posts: 29
Joined: 10. Nov 2008, 18:51
Primary OS: Mac OS X other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Win7, ClearOS, SnowLep, CAELinux

Re: Medium is differencing but not associated with any parent???

Post by nuke »

Thanks for the reply Perryg.

I uninstalled v3.2.8 with the uninstall script and then installed v3.2.6 again. It didn't fix anything. I guess the damage was already done.

Yes, there were snapshots in the WinXP guest. Yes, everything was shutdown, saved and turned off before I did the update.

====
I have a backup copy of the guest, so I removed v3.2.6 and reinstalled v3.2.8 again. This time I deleted all the problem media disks and deleted the guest setup. Shutdown and restarted VBox. Then I imported the saved/backed up WinXP guest. When it was finished reimporting, everything is OK except that I lost the snapshots. So I have to reinstall some software to rebuild the snapshot.

There is something wrong with the updating function as the guest shouldn't have lost the original and main hard drive. There must be someway to fix this without going through a full reimport etc.
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Medium is differencing but not associated with any parent???

Post by Perryg »

At this point I am not sure what has caused this problem. I do know that (IMHO) snapshots are a pain and I don't use them. I got burned once and lost a lot of time rebuilding so well there you have it.

I do know that I have upgraded (3) hosts and all of their guests so far and no problems (knock on wood).
Each host has approx 20 guests and are Linux, Windows, & Solaris.

The reason that I asked if the guest was shutdown instead of being in a saved state is because from what I can tell the guest does not write back to the xml file until complete shutdown and if in a saved state (could) appear as a plug pull. Just a theory I am working on.

With all of this said, it is my opinion that if you are going to insist on using snapshots you should do a complete backup of all .VDI, SAV, Etc. files and XML files to be able to restore if something bad happens.
nuke
Posts: 29
Joined: 10. Nov 2008, 18:51
Primary OS: Mac OS X other
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Win7, ClearOS, SnowLep, CAELinux

Re: Medium is differencing but not associated with any parent???

Post by nuke »

Yes, I guess I'll be making backup/export guest prior to a software upgrade a step in the process. It means that any update will take a bit of time.

Is there a way to automate an export guest on Mac .... maybe using Applescript or something like that? Or Bash code with the command line?
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Medium is differencing but not associated with any parent???

Post by Perryg »

Honestly I am not that well versed in MAC but I just backup the .VirtualBox folder and all sub folders to an external TB drive. I have created a batch file for windows and a script for *NIX. Also keep in mind that the snapshots can get to a large size if you use them a lot. On Windows I usually have the VirtualBox program on a different drive completely so I also backup the VirtualBox.xml that is stored in the user space folder.
jvlopez
Posts: 1
Joined: 7. Aug 2010, 22:05
Primary OS: Ubuntu 8.10
VBox Version: VirtualBox+Oracle ExtPack
Guest OSses: Ubuntu 9.10 Server

Re: Medium is differencing but not associated with any parent???

Post by jvlopez »

I have a similar problem

Medium type of '/home/XXXX/.VirtualBox/HardDisks/Karmic.vdi' is differencing but it is not associated with any parent medium in the media registry ('/home/XXXX/.VirtualBox/VirtualBox.xml').

any one can help me please??
Perryg
Site Moderator
Posts: 34369
Joined: 6. Sep 2008, 22:55
Primary OS: Linux other
VBox Version: OSE self-compiled
Guest OSses: *NIX

Re: Medium is differencing but not associated with any parent???

Post by Perryg »

I suggest that those having this problem re-post here http://forums.virtualbox.org/viewtopic.php?f=1&t=33518

Since this appears to be a regression you need to keep it in one place for the DEVs to look over. I am going to lock this topic so no one else posts this problem here.
Locked