

If you are running Ubuntu and your system randomly crashes, you may be running out of memory. run pm-suspend (will suspend the machine) start the machine you should get the machine back to the state before the screen freezes (at least for me it did) Why does my Ubuntu keeps freezing?

Instead, RAM is allocated on request of the guest VM when actually required. The reason is that VirtualBox by default does not allocate all of the RAM that you have configured for the VM. Sometimes you may find that a guest virtual machine under a Windows based VirtualBox host freezes. Why is my Ubuntu virtual machine so slow?.

