Failed to start VM error

estrahon · Post by **estrahon** » 28. Oct 2008, 23:54

Hi, I just upgraded to VB 2.0.4 and have Fedora 8 as a guest on a Vista host. After doing some work in my vm I powered it down for the night after saving the state. I came back several minutes later and virtualbox had opened itself up and somehow rebooted Fedora. Confused I powered it back down and saved it again just in case, however the save lasted 5 minutes when it only takes a couple seconds on my pc. The next morning I try to open up Fedora and I get this message:

Besides upgrading I didn't do any weird changes, just my usual work. A bug perhaps? Is there a fix or am I going to have to discard all of my work. And if I do how do I prevent this from happening again when my server goes into production mode?

Post by **TerryE** » 29. Oct 2008, 01:32

The sav file is what stores your VMs memory when you suspend it. You can discard this which is basically the same as powering off the machine. Don't discard the snapshot which will discard the {UID}.vdi in the Snapshots directory. You will loose what is in memory but not on disk.

It is always sensible to cleanly power off your VMs before you upgrade.

estrahon · Post by **estrahon** » 29. Oct 2008, 19:48

Thanks for the reply I'll keep that in mind. However, I did completely power down machine before I upgraded so I don't think that caused the problem. Here's an update after I asked my question:

I closed out vb after I got the previous error and reopened it and was able to boot off my originally saved state as if nothing had happened. And now when I open up VB I get this warning:

I then check to see what it's talking about and it shows me that this file is missing:

Note: I never touched my files so I don't know why it keeps giving me these errors. It says that I won't be able to operate my vm until I replace it but I'm able to boot up Fedora just fine. It's just annoying.

estrahon · Post by **estrahon** » 29. Oct 2008, 19:54

Update: Well I was wrong, now it won't let me boot up at all.

Post by **Sasquatch** » 29. Oct 2008, 21:10

The problem is that your snapshot cannot be found. Check your snapshot folder and see if the file is there or not.

estrahon · Post by **estrahon** » 29. Oct 2008, 21:29

I checked my folder and all of my snapshots are there. I'm just going to have to delete everything and reinstall.

estrahon · Post by **estrahon** » 29. Oct 2008, 22:01

I took TerryE's comment and deleted all of my .sav files that way I can just run off of my clean snapshot. My OS booted fine and so I closed it back out by saving the state first. I closed out VB and the warning went away. Then I booted my OS back up and closed it out again by saving the state first and then closed out VB once more. I hope I'm not confusing you but upon opening VB once more, this time the warning came back up saying that my snapshot was missing. I looked in my folder to find the snapshot it wanted and the same file was still there.

Post by **Sasquatch** » 30. Oct 2008, 23:40

The file might be there, but what size does it have? If it's an empty file, it will give the same error, as it can't find the file headers or other information.

estrahon · Post by **estrahon** » 31. Oct 2008, 05:00

Thanks for your other reply. I had two .sav files but one was empty so I deleted that and tried to run off the other. Eventually it kept making empty files so I just wiped everything clean and created a new install. I'm worried something like that will happen again. Obviously I'm a newbie, are snapshots even necessary? Will I be able to get away with just saving the state as I close? I think I just want to avoid the snapshot feature to prevent the file being messed up again.

Post by **Sasquatch** » 1. Nov 2008, 17:06

estrahon wrote:Thanks for your other reply. I had two .sav files but one was empty so I deleted that and tried to run off the other. Eventually it kept making empty files so I just wiped everything clean and created a new install. I'm worried something like that will happen again. Obviously I'm a newbie, are snapshots even necessary? Will I be able to get away with just saving the state as I close? I think I just want to avoid the snapshot feature to prevent the file being messed up again.

It depends. Why were you useing snapshots in the first place? If you close the VM by issueing a Save State, then the memory of the VM will be saved to a .sav file, just like how you would hibernate your Windows Host and the active memory is written to C:\pagefile.sys and it will resume from the contents in that file upon next boot.

Snapshots can be used to save a specific setup state, e.g. if you want to install a new program but don't know what it will do or if you want to keep it. You can then restore to the created snapshot to go to a state before the installation of that program.