Virtual Machines disappear [Solved]

[shahgols]

Hi everyone,

I have been having a problem for a while and even when I upgraded to the latest virtualbox or installed from scratch, the problem persists. The problem is that once in a while the virtual machines disappear from the list of machines and I have to add them again manually. I am not sure if virtualbox keeps any logs that I can post here, so let me know what information you need and how to get it and I'll post it. Many thanks!

Forgot, I am running Win 7 Pro 64-bit and my guests are linux (Debian and PCLinuxOS). Virtualbox version is 4.2.6 r82870.

[shahgols]

Does anyone know if the support people or developers visit this forum? My problem might just be for them.

[Perryg]

Devs do drop by from time to time but not on a regular basis. The missing from the list is not a usual problem and I have only read about it one other time. In any case the VirtualBox.xml is the control file that keeps track of this and it would mean that for some reason it is either being corrupted or missing. This would be a host issue I am afraid, unless you power the guests down hard instead of the proper way. This might cause your issue.

[shahgols]

Thanks Perryg, I appreciate your help. The guest machines are shut down cleanly. I'll keep an eye on the xml file and see if it is being corrupted or changed in any way. I'll let you know.

[Perryg]

I would make a backup of the file whenever you make changes (do this with everything VBox shut down) and the next time it happens shut down everything VirtualBox and replace the current one with your backup and see if it fixes the issue. If so then you need to find out why it is getting changed.

[shahgols]

I found the VirtualBox.xml and another file, VirtualBox.xml-prev files.

This morning I had manually added the guest machines, since they were again gone. The xml-prev file had a date stamp of today, so I am assuming that it was the xml file that existed when the machines were not showing up in the GUI.

I compared both files and they are the same. I went one step further and copied the xml file to another location and replaced it with a copy of the xml-prev file and the GUI showed the guest machines. So these files are not corrupted, something else must be causing this issue.

[shahgols]

Hi Perry, you replied as I was replying to you. I did as you had asked, please read my previous post. Thanks!

[Perryg]

Did you see the guest/s that were missing in the file?

Where are the guests stored?

[shahgols]

Yes, I saw both guests.

They are stores at C:/Users/<my username>/ directory.

[Perryg]

You should have several VBoxSVC.logs in your userspace. Look at them and see if they show any issues. Also are you doing anything out of the ordinary when starting the guests? Desktop shortcut, start as service, Etc.?

[Perryg]

Another thing to check.

Do you always start VirtualBox as the same user?

[shahgols]

Just wanted to add a few things. I have not been able to reproduce this error. I have seen no patterns at all. Application/System events show no errors/warnings either. This Win 7 installation is 6 months old. The apps installed are minimal, including:

SQL Server 2012 Developer edition (full install, including client apps)
MS Visual Studio 2010

I have almost the same setup at home, and all is fine. In fact, before I reinstalled Win 7 on this machine, I had VB and I didn't have any problems with it.

[shahgols]

Yes, I am always logged in as myself. I did try running it as Admin, thinking that it might be some sort of a permissions issue, but had the same problem.

[Perryg]

Assuming this is a company PC, is it possible that a group policy or some other script may be getting run after hours that would change this?

[shahgols]

No, this happens all throughout the working day.

I just lost the list of guest machines, I opened the .VirtualBox folder and the VirtualBox.xml file was gone. I closed and started VirtualBox again, a new VirtualBox.xml file appeared and it doesn't have the guest machines in it. I am not sure how this happens though.

Hold on, I'll add an exception for this file in my anti-virus. Let's see if that helps. Let me know if you have any other ideas. Many thanks Perryg.