What to do if Windows 8 Release Preview won't install

Some users have bumped into installation errors with the latest flavor of Windows 8. Microsoft says you may need to tweak or update your BIOS to solve the issue.

Lance Whitney Contributing Writer
Lance Whitney is a freelance technology writer and trainer and a former IT professional. He's written for Time, CNET, PCMag, and several other publications. He's the author of two tech books--one on Windows and another on LinkedIn.
Lance Whitney
3 min read
Some users are having trouble installing the Windows 8 Release Preview.
Some users are having trouble installing the Windows 8 Release Preview. Screenshot by Lance Whitney/CNET

Have any of you tried to install the new Windows 8 Release Preview only to face the message: "Your PC's CPU isn't compatible with Windows 8."

If so, the solution to the problem may lie in your computer's BIOS.

Several perplexed users chiming in on Microsoft's Answers forum have all reported similar errors when trying to install the new Release Preview. I myself ran into issues when I tried to install the RP as a virtual machine on one of my laptops.

The first step suggested by Microsoft is to see if the following features are enabled on your CPU: Physical Address Extension (PAE), NX, and SSE2.

"Most CPUs have support for these features, so if you receive this error, it is likely because the NX feature is not enabled on your system," Microsoft explained in the forum. "To resolve this error, follow manufacturer guidelines to enable NX ("No eXecute bit"), or the equivalent XD ("eXecute Disabled") feature, within the BIOS security settings."

Hmm, OK, Microsoft, we'll bite.

To get to the BIOS setup page, you typically need to press a certain key, such as Esc or F2, depending on your PC. Well, what happens if you don't see any of settings listed by Microsoft? A phone call to your PC maker's tech support may be in order.

But your best bet may simply be to update your BIOS, assuming it's not already current. To do that, you'll need to check your PC maker's tech support page for a section called Drivers and Downloads or something similar. Within that section, you should see several updates, including one for your BIOS.

Updating the BIOS can be a dicey matter if something goes wrong. So you'll want to make sure that the BIOS update listed is the one for your specific PC. Several manufacturers now offer software that you can download through your browser to detect your make and model PC and pinpoint the correct drivers.

You should run a full backup of your PC before you update the BIOS just as a precaution. But generally, updating the BIOS is a quick and automatic process. After the BIOS has been updated, you can then try to reinstall the Windows 8 Release Preview to see if it works.

I was initially unable to install the RP as a virtual machine on my laptop. But after updating the BIOS, the installation ran without a hitch in both Oracle VirtualBox and VMWare Player.

So two questions pop up here: 1) Why are users running into BIOS issues with the Release Preview, but not with the Consumer or Developer Preview? I, at least, had no trouble installing the previous versions of Windows 8 with the older BIOS; and 2) Could this issue affect the final release of Windows 8?

CNET contacted Microsoft for comment and will update the story when we get more information.

The company did attempt a response in the Answers forum, apologizing for the inconvenience and explaining some of the changes in the Release Preview related to the CPU.

Yet it also aired a note of caution, revealing that there could be a glitch afoot.

"There may be a bug here," Microsoft said in its response. "We may contact a few of you if we need further information to track down the problem and make sure it is fixed before RTM (release to manufacturing) completes."

If there is a bug, let's hope Microsoft can track it down and resolve it in time. Windows 8 is already likely to prove a hard sell for many users. The last thing the company needs are throngs of people who can't even install the OS because of BIOS and CPU issues.

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