virtualbox.org

Hi,
I've had a Windows 8.1 Pro x64 VM running on VBox 4.3 for a few days now with no issues at all.

However, this morning, the VM refused to boot saying VT-X was not enabled.

I checked via the VM settings but the whole "Acceleration" pane was disabled and not accessible. I was not able to resolve the issue even after rebooting my PC and explicitly enabling Intel Virtualization in the PC BIOS.

I therefore several times removed the VM completely and attempted to reinstall.

Every time, the VM hangs on the Windows 8 logo screen on install and then crashes with the Error 0x000000C4 and varying parameters.

As found on VirtualBox community forums and on other sites, I have tried the SETEXTRADATA command via command prompt running as administrator, and have confirmed that the .vbox file has been changed and the string ExtraDataItem name="VBoxInternal/CPUM/CMPXCHG16B" value="1" appended in the <ExtraData> section.

However the VM still refuses to boot or reinstall. I have Ubuntu, Fedora and ZorinOS VM's working perfectly.

PC Specs:
Intel Core i7 3770K on ASRock Z77 OC Formula with 16GB DDR3, GTX470, Windows 7 Ultimate x64 on SSD system disk.
VirtualBox version: 4.3.12 r93733 with Extension Pack 4.3.12 r93733.

The only change to my system that took place in the interim was that I installed Comodo Free Firewall last night. Seeing the problems I have been having with the VM since this morning, I uninstalled Comodo and rebooted thinking it might have something to do with my problems, but still no joy.

I am also uploading my .VBOX files before and after to show the changes that have been made by the SETEXTRADATA command.

This may be Off-Topic here, but I just tried to install Windows 8.1 Pro x64 from the same ISO file on VMWare Workstation and Player, and get the same 0x000000c4 error on both. This is the same PC as I was trying to use with VirtualBox.

Upgraded VBox to 4.3.14, got initialization errors, downgraded to 4.3.12, which gives me the same 0x000000c4 error on installation of windows 8.1.

Is this then an error that is not specific to VirtualBox but something originating somewhere else in the system/PC?

Funniest thing is that VBox was running that install of Windows perfectly till this morning.

VBox.log wrote: 00:00:19.263347 CPUM: WARNING! Can't turn on NX/XD when the host doesn't support it!

Your host is incapable of running Win8.1 natively, so it can't run it as a guest either.

The CPU and motherboard are an Intel Core i7 3770K and an ASRock Z77 OC Formula respectively.

I doubt the inability of the hardware is an issue here.

Win8.1 was running flawlessly until yesterday. The whole issue only started this morning.

Ah, I didn't catch that from your original post.

In that case you must have installed something else on the host that wants VT-x/AMD-v.

Nothing new, just Comodo, and I removed it as soon as I started getting my issues with the WIndows 8.1 VM in version 4.3.12.

pillainp wrote:Nothing new, just Comodo, and I removed it as soon as I started getting my issues with the WIndows 8.1 VM in version 4.3.12.

Reboot the physical?

Several times, but to no avail.

Ok, 2 days ago I ended up with the same problem. But I use two partitions partition one Windows 7 Pro and partition 2 Linux Ubunut 14.04
I installed windows 8.1 in virtual box 4.3.12 under Linux. Previously I had 3 partitions, partition 1 windows 7, Partition 2 Linux and partition 3 Windows 8.1.
I was testing to see how well I liked windows 8.1. I decided I wanted in on virtual and decided to keep windows 7 and moved the partition 3 to data for Virtual storage room.
I set it up windows 8.1 virtual to work in Windows 7 and then 2 days ago I wanted to check something while in windows 7 and the Error 0x000000C4 came up.
So for the past two days I thought it was something with Virtual Box.
I down loaded the windows 8.1 Pro 32 bit, It did the same thing.
So I thought about it and what version of virtual box did I use that actually worked with windows 8.1 in virtual box.
I have not un installed virtual box yet, but did discover that 4.3.14 does not work and errors out, and had to down grade back to 4.3.12
It works perfectly under linux. But under windows 7 it come up with the error. I even tired my windows 8 plain iso and it did the same thing
I decided to check here and see if this problem is going around.

Previously I made a post on here that I think virtual box in windows was passing to much information over to the virtual machine. In Windows I did not have the virtual box system setting for processor set for Enable PAE/NX, yet to have my windows 7 virtual run in Linux it had to be enabled.

So have they now blocked out more than needs to be with virtual box or? do we have a malware causing us to be unable to run windows 8, or windows 8.1 or? Has a windows update blocked something that is needed in windows 8.1.

I'd appreciate and answer too.

I'm wondering if one of the new system updates is blocking hardware virtualization information from reaching VBox.

I keep seeing comments on mine and other threads about systems being reported as incapable of virtualization when in fact they are.

For example, this from my log:

mpack wrote:

VBox.log wrote: 00:00:19.263347 CPUM: WARNING! Can't turn on NX/XD when the host doesn't support it!

Your host is incapable of running Win8.1 natively, so it can't run it as a guest either.

But my CPU (Intel 3770K) and motherboard (ASRock Z77) do indeed support virtualization as does Windows 7 Ultimate x64, which is my host OS.

So is something preventing VBox from seeing that the host is indeed capable of virtualization?

Also while I think there are specific issues with VirtualBox, I think that is not all there is to the problem.

I am getting the same error code from a Windows 8.1 VM installed in VMWare Workstation, while a concurrent Fedora 19 VM in VMWare works perfectly.

This is why I am drawn to think something has changed on the Windows 7 host over the past couple of days that is causing part of the problem.

DWade wrote:Ok, 2 days ago I ended up with the same problem. But I use two partitions partition one Windows 7 Pro and partition 2 Linux Ubunut 14.04
I installed windows 8.1 in virtual box 4.3.12 under Linux. Previously I had 3 partitions, partition 1 windows 7, Partition 2 Linux and partition 3 Windows 8.1.
I was testing to see how well I liked windows 8.1. I decided I wanted in on virtual and decided to keep windows 7 and moved the partition 3 to data for Virtual storage room.
I set it up windows 8.1 virtual to work in Windows 7 and then 2 days ago I wanted to check something while in windows 7 and the Error 0x000000C4 came up.
So for the past two days I thought it was something with Virtual Box.
I down loaded the windows 8.1 Pro 32 bit, It did the same thing.
So I thought about it and what version of virtual box did I use that actually worked with windows 8.1 in virtual box.
I have not un installed virtual box yet, but did discover that 4.3.14 does not work and errors out, and had to down grade back to 4.3.12
It works perfectly under linux. But under windows 7 it come up with the error. I even tired my windows 8 plain iso and it did the same thing
I decided to check here and see if this problem is going around.

Previously I made a post on here that I think virtual box in windows was passing to much information over to the virtual machine. In Windows I did not have the virtual box system setting for processor set for Enable PAE/NX, yet to have my windows 7 virtual run in Linux it had to be enabled.

So have they now blocked out more than needs to be with virtual box or? do we have a malware causing us to be unable to run windows 8, or windows 8.1 or? Has a windows update blocked something that is needed in windows 8.1.

I'd appreciate and answer too.

This is just about the exact history I have, except I was single-booting Windows 7 and running Linux in a VM. All was working perfectly till yesterday morning, when, just like you, I went to start the Windows 8.1 VM from my Windows 7 host, and ran into this 0x000000c4 error. Linux continued to run perfectly in the VM.

The question then becomes, When was the last date that the Windows 8.1 VM was working in Windows 7.
Before July 2014 Windows Updates, Before June 2014 updates.? or eariler?

And more importantly why does virtual box 4.3.14 not work in Windows 7.

Then once these are answered which update is causing the problem.

And If not a Update, Then what kind of malware is attacking Virtual Box to stop Windows 8 all versions and 8.1 all versions, from working or being installed.

I know for certain that VirtualBox was working fine on 22 July 2014 latest. Version 4.3.12

Installed Comodeo on 22 July 2014.

VBox stopped working with Windows 8.1 VM's (error 0x000000c4) on 23 July 2014. Version 4.3.12. Removed Comodo. VBox continues to error out with Windows 8.1 VM but Linux works

VBox system startup error following upgrade to 4.3.14 ----> 4.3.12 ----> 4.2.26 ----> 4.3.15 1st test Build

Upgraded to 4.3.15 2nd Test Build (Currently running) on 24/25 July 2014.

As of now VBox itself starts fine, but gives 0x80004005 on starting any VM, Windows or Linux.

Occasionally I also receive a "VT-x is disabled in BIOS" error (even thought I have verified multiple times that it is) ----- at this time, Acceleration pane is disabled in the VM's settings System page. Powering down and restarting the VM recreates the 0x80004005 error.

I have Suggestion for you.
Download Ubuntu Linux(32 or 64 bit), and let it install itself beside windows, go to download here and download the corresponding 4.3.12 Virtualbox, Install and install the Extension pack, make a Windows 8.1 machine setting using the existing Windows 8.1 VDI. In linux you will have to Mount the disk your virtual is located in, every time. More Instruction if needed can be given.

My Ubuntu Linux, 14.04 64 bit works fine with Virtual Box and windows 8.1
I do not have PAE/NX enabled. Included a screen shot of it now.

I do not use Comodo antivirus, so it not the AntiVirus causing the problem. I will try one more item. I will replace my MBR.
I completely uninstalled Virtualbox. I cleaned up the registery and all folders.
I reloaded starting with 4.2.2, going up all the way to 4.3.4 --- Same Problem
What I have not stated is that Window 8 Pro gives a different Error Code of OxOOOOO5 E I think I will have to go to Windows and redo it again to verify.

I went to another hard drive with a same partition of windows but not loaded with all my extra stuff, but it had been updated by me to July's Microsoft Updates and it did the same thing.

If the MBR does not work, I will then restore my windows partition to my backup of August 2013. But I will Post first.

Just a few notes...

The VBoxInternal/CPUM/CMPXCHG16B is not relevant for any VirtualBox version which includes Windows 8.1 as a guest type. If your VM is already set to Windows 8.1 guest type, adding the extradata setting will do no good whatsoever.

The reason why Fedora guests work and Windows 8.1 does not is that the latter has higher hardware requirements.

The real problem seems to be that your CPU suddenly lost the NX/XD (Non-eXecutable/eXecute Disable page) feature. Which is why VMware has the same problem. So yes, the inability of your hardware in fact is exactly the issue. That said, your CPU of course does support the feature, which means it somehow got disabled. How it got disabled and how you can get it back is unfortunately not something we can tell you.