Ubuntu 14.04 crashes randomly on a Windows 8 host

[emanuel]

Hello,

since several days now, I've started seeing this error soon after starting the VM: "The instruction at 0x800839e0 referenced memory at 0x00000000. The memory could not be read".
I'm attaching the logs where I can see a suspect line: NAT: IPv6 not supported.

I'll try exploring different network settings but any suggestions are welcome.

VirtualBox: 4.3.20 r96997
Host OS: Windows 8.1
Guest OS: Ubuntu 14.04 with Guest Additions installed

Thank you,
Emanuel

[mpack]

00:00:04.861345 Host RAM: 3981MB total, 1920MB available
...
00:00:06.440504 RamSize <integer> = 0x000000007c600000 (2 086 666 240, 1990 MB)
00:00:06.440851 VRamSize <integer> = 0x0000000008000000 (134 217 728, 128 MB)

Your host doesn't have enough available RAM for this VM: 1990+128 >> 1920.

Also, your host has a dual core CPU (Intel spec here). Assigning both cores to the guest doesn't leave much for the host. To answer the inevitable "but": cores and threads are not the same.

I see that your VM is using 3D acceleration. That too can sometimes be unstable. You should check whether newer graphics drivers are available for your host.

You have not installed the extension pack on the host: you will not be able to use USB2.

I can't tell if you have installed the Guest Additions in the guest: the provided log file is not for a completed session.

[emanuel]

Hi there, I've made all the suggested changes except disabling 3d acceleration and issue is now fixed.
Many thanks for the prompt solution!

Specifically I've done the following:
Decreased allocated RAM from 1990 to 1750 MB
Decreased number of cores used by the VM from 2 to 1.
Installed extension pack on the host.
Guest additions were already installed but gave it another go anyway.