FIX: CompareExchange128 / CMPXCHG16b problem in Windows 10

As you probably know, Windows 10 is free for most Windows 7 and Windows 8.1 users, but that doesn’t mean that upgrade to Windows 10 is always smooth.

Users report having a CMPXCHG16b / CompareExchange128 issue when upgrading to Windows 10, so let’s see how can we fix that.

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How do I solve the CMPXCHG16b / CompareExchange128 error?

CMPXCHG16b is a special CPU instruction this is required in order to upgrade to Windows 10, and some processors lack this instruction so you won’t be able to upgrade to Windows 10.

Changing your processor is usually expensive, especially if you have an older CPU that doesn’t support CMPXCHG16b instructions, so let’s see how we can fix this issue.

In the following video tutorial, we offer some helpful solutions and advice to work around this issue. Make sure to check it out and then continue with the upgrade process described just below.

1. Use third-party Windows repair tools

Whenever you have difficulties with the booting aspect of using a PC, then it’s most likely to fix it using dedicated programs that will improve system issues.

You can use built-in services on your Windows to resolve this, like booting in Safe Mode or Startup Repair options. With these options, you can manage to fix booting troubles manually.

Otherwise, if this is not working, you should opt-in for specialized programs that are capable to fix booting issues, system crashes or recovering essential lost data.

Thereby, it’s advised to choose the most efficient Windows 10 boot repair tools to revise your system immediately.

You will no longer have to go for more drastic solutions, such as performing a total PC reset, especially since they can result in data loss if done incorrectly.

2. Upgrade to a 64bit version of Windows 10

If you’re planning to upgrade to a 64bit version of Windows 10, you will need a processor that supports CMPXCHG16b instruction, but you can upgrade to a 32bit version of Windows 10 without any major issues. This is a workaround and not the best solution, but it’s worth giving it a try.

1. Download 32-bit version of Windows you’re currently using and install it instead of your current version.
   • Make sure that you create a backup for your important files.
2. Download all the updates and when you get asked to upgrade to Windows 10, do so.
3. You’ll upgrade to a 32bit version of Windows 10, and it will be activated on Microsoft’s servers.
   • The great thing about this is that activation is limited only to your hardware, not to the version of Windows 10 you’re using.
4. Download 64bit version of Windows 10.
5. Use Creation Media program and choose to Create installation media for another PC.
   • You’ll need an empty DVD or USB flash drive to complete this step.
6. Perform a clean install of Windows 10 but remember to skip the step when asked to enter the serial number.
7. Once the installation is complete, you’ll have activated and working 64bit version of Windows 10.

That’s about it, if you have any questions, comments or suggestions, just write them down in the comments, below.