Ubuntu Linux froze in VirtualBox

Question

I am working on the newest version of Ubuntu Linux on VirtualBox under a 64-bit Windows 7 host. When I was working, VirtualBox froze, and I hadn't saved my work in Ubuntu. What should I do?

(This happened after I installed the extension pack for USB 2.0 and I went ahead and tried to access a USB port. I suspect that this led to my current situation.)

Solution

There are two ways Virtualbox can "freeze". One is that the guest OS (i.e. Ubuntu) or the kernel mode VM code is not being scheduled or is locked up. There's not much you can do in this case.

If it's the GUI that is freezing (happens quite frequently if due to display driver or other bugs), you might be able to access your guest OS through SSH or VRDP. Of course you must have these setup before the freeze occurred.

If not, you can try your luck with the vboxmanage controlvm command. Use the savestate function to store the current OS state to disk, and then you can close the crashed VBox and open it again.

Comments

[Prasanth Ganesan]

This happened after I installed the extension pack for USB 2.0 and I went ahead and tried to access a USB. This led to my current situation.

[Randolf Richardson]

Is Windows 7 up-to-date with the current Server Pack? I've noticed that Service Pack 1 resolves some freezing issues in Windows 7.

[Prasanth Ganesan]

What does it mean for the guest OS to be locked up or not being scheduled? How do I know which is which? Also if I access my guest OS with VRDP (which I don't have set up yet), can I get back to my original workspace?

[Prasanth Ganesan]

Will using "vboxmanage controlvm" delete my unsaved files?

[Prasanth Ganesan]

Will it "unfroze" over time? Thank you for your help.

[billc.cn]

Frankly not being scheduled only apply to the VM code in your host kernel. This can only happen due to some bug in VBox or conflict with some driver. Lockup in the Linux kernel is quite rare as well, but it can happen if some driver is not well written.

[Prasanth Ganesan]

Even the VirtualBox manager froze. What does that mean?

[billc.cn]

If you use savestate, Vbox will save all the memory contents and other machine states to the disk and then close the VM. That is if the VM is still "alive" and accepting external controls. Otherwise you can wait for awhile to see if the VM unfreeze or not. If you're using Windows Vista/7 and the window has already turned "grey", then it will probably never restore.