Tag Archives: windows8

VirtualBox CompareExchange128 Error

Today, I attempted to upgrade my Windows 8 machine to the yet-to-be-released Windows 8.1, and I got the following error:

You can't install Windows 8.1 because your processor doesn't support CompareExchange128.


I am running 64-bit Mac as my primary operating system, and have set up 64-bit Windows 8 on a VM using VirtualBox.


One of the additional system requirements for 64-bit Windows 8.1 installation is that the CPU must also support CMPXCHG16b, PrefetchW and LAHF/SAHF. And this setting is disabled in VirtualBox by default.

Please check out this link for the other system requirements for Windows 8.1.


Open up the command prompt of your choice – Terminal / iTerm, and execute the following command:

VBoxManage setextradata [VM_Name] VBoxInternal/CPUM/CMPXCHG16B 1

And, that’s it! You’re ready to install Windows 8.1!


VirtualBox error: Kernel driver not installed (rc=-1908)

I use VirtualBox to  run a Windows 8 VM on my Mac. Something strange happened today. My Mac ran out of battery while I was working on something important on the Windows VM. I recharged my Mac and tried to restart the VM, but the VM was not booting up at all. I kept getting the following error:

VirtualBox error: Kernel driver not installed (rc=-1908)

Since the machine had not shut down gracefully, the VM seemed to have got corrupted.

After spending quite a bit of time trying to troubleshoot this problem, I was finally able to resolve it. Reinstalling VirtualBox helped resolve the issue. Obviously, I did lose all the unsaved changes, but the good part was that the VM was still intact, and it booted up just fine!

Just penning it down so that it helps someone else facing the same issue…

‘Hybrid’ Boot Mode in Windows 8

Came across this article on Technospot.net today regarding the ‘Hybrid’ boot mode of Windows 8. I have Windows 8 Developer Preview installed on my machine, however when I tried to search for the ‘Hybrid boot’ option under ‘Power Options’, I did not find any.


Does anyone know the reason behind this? Has somebody else faced this as well?

Windows 8 Developer Preview

Just installed the Windows 8 Developer Preview on my Windows 7 machine off a VHD (Virtual Hard Drive). Looks awesome! Thanks to the detailed blog by Scott Hanselman.

Windows 8 Developer Preview also offered a boot-loader allowing dual boot between Windows 7 and Windows 8 Developer Preview. So, I can still run Windows 7, and play around Windows 8 in my spare time. Really excited..!! Smile