Windows cannot be installed on VirtualBox, CompareExchange128 Processor Incompatibility



Updated April 2024: Stop getting error messages and slow down your system with our optimization tool. Get it now at this link
  1. Download and install the repair tool here.
  2. Let it scan your computer.
  3. The tool will then repair your computer.

A few days ago, we reported a bug we just had when installing Windows 8.1 Preview on VirtualBox. As we all know, VirtualBox is the safest way to try preview versions, as it provides all the necessary requirements for the Windows edition to be tested. Today we had another problem with the installation of Windows 8.1 on VirtualBox. This time we have an error window: Your PC does not support CompareExchange128. Here is the screenshot:

This seems to be a compatibility issue closely related to virtualization, since Windows 8 runs on the same PC. However, VirtualBox settings must be respected if you decide to install an operating system, in addition to the normal requirements specified for this. VirtualBox has a solution for that.

The patch is mentioned below, but make sure you run it if VirtualBox doesn’t work on your system.

Windows cannot be installed because the processor does not support CompareExchange128

April 2024 Update:

You can now prevent PC problems by using this tool, such as protecting you against file loss and malware. Additionally, it is a great way to optimize your computer for maximum performance. The program fixes common errors that might occur on Windows systems with ease - no need for hours of troubleshooting when you have the perfect solution at your fingertips:

  • Step 1 : Download PC Repair & Optimizer Tool (Windows 10, 8, 7, XP, Vista – Microsoft Gold Certified).
  • Step 2 : Click “Start Scan” to find Windows registry issues that could be causing PC problems.
  • Step 3 : Click “Repair All” to fix all issues.

Download Now

1 Open Prompt Command with administrative rights.

2 Enter these commands one by one, then Enter key :

cd'C:Program FilesOracleVirtualBox'. ] VBoxIntern/CPUM/CMPXCHG16B 1

User (not administrative Command prompt). Restart and try installing Windows 8.1 using virtualization, and this time you will not get the error.

This article refers to 32-bit preview of Windows 8.1, if you want to install 64-bit version Windows 8.1, then your processor must support CMPXCHG16b, PrefetchW and LAHF/SAHF.

I hope you find the solution useful!

If you receive the error message’Your Windows installation could not complete’, check this message.



Expert Tip: This repair tool scans the repositories and replaces corrupt or missing files if none of these methods have worked. It works well in most cases where the problem is due to system corruption. This tool will also optimize your system to maximize performance. It can be downloaded by Clicking Here

Related Video

Scroll to Top