Many people who are trying to install Windows 8 Release Preview
are reporting an error, you may see the following error message::
Quote:This PC can’t run Windows 8
Your PC’s CPU isn’t compatible with Windows 8
This error has been reported even by those who could run Windows 8 Consumer Preview on the same machine. While installing Windows 8 Release Preview.
So what has changed since the Consumer Preview? Let us check what this error is and what Microsoft is saying about it.
As we can see, this error is related to CPU requirements for Windows 8 Release Preview. So to install Windows 8 RP, your CPU (processor) must support these features – PAE/NX/SSE2 .
Let us see what these means.
“No-eXecute (NX) is a processor feature that allows marking of memory pages as non-executable. The feature allows the CPU to help guard the system from attacks by malicious software. When the NX feature is enabled on a system, it prevents malicious software code from being placed in accessible regions of memory to be executed when control reaches that memory location. Windows 8 requires that systems must have processors that support NX, and NX must be turned on”
“Streaming SIMD Extensions 2 (SSE2) is a previous standard that is supported in Intel and AMD processors. All processors that support NX also support SSE2.”
"To use the NX processor feature, the processor must be running in Physical Address Extension (PAE) mode. PAE is a processor feature that enables x86 processors to access more than 4 GB of physical memory on capable versions of Windows. "
The processor requirement won’t impact customers on modern systems, or on systems that meet logo requirements for Windows 7 because these systems have PAE-capable 32-bit processors that support NX and allow NX to be turned on. Only a small set of customers who have Windows 7 running on very old 32-bit processors without PAE/NX support will be impacted.
Check if your system Supports NX or SSE2
To check this, there’s a Windows Sysinternals tool Coreinfo , a command-line utility. You can get it from here
. Running this from the command line, will provide the required info -
A supported processor feature will have the * character displayed next to the feature name, and a - character if not supported.
“If PAE is displayed as not supported in Coreinfo output, your system has a processor that is not PAE-capable, and cannot support NX. If PAE is shown as supported, but NX is displayed as not supported in Coreinfo output:
· Consult the feature set published by the CPU manufacturer to determine if NX is supported by the processor on your system.
· If the processor on your system does have the NX support, then your system may have misconfigured BIOS setting for NX support option.
If NX is supported on your system, can be turned on from BIOS settings if its not turned On.”
So check the BIOS and enable NX (“No eXecute bit”) or the equivalent XD (“eXecute Disabled”) feature in the BIOS settings. Look them in Advanced or Security options in BIOS. They may be referred by various names according to BIOS manf. They can be named No Execute Memory Protect, Execute Disabled Memory Protection, EDB (Execute Disabled Bit) , EVP (Enhanced Virus Protection) or by some oth name. So check for these.
If the BIOS doesnt show any of these option for NX , then check with BIOS manf for any BIOS updates which might have added this. Very old processors may not include this feature.
A related error is also seen in when trying to install Windows 8 in a VM with an error 0×0000260.
“If the Virtual Machine (VM) is hosted on a system that supports NX, you must enable PAE/NX in the virtualization product’s settings or configuration manager when setting up the Windows 8 virtual environment. “
For more detailed info on PAE/NX/SSE2 requirement for Windows 8, Microsoft has published a Whitepaper - PAE/NX/SSE2 Support Requirement Guide for Windows 8
This document details the processor support for the PAE/NX/SSE2 requirement in Windows 8, error cases and scenarios that customers encounter when machines fail to meet the requirement, and what to do to install Windows 8 on their PCs. The information provided in the document applies to Windows 8 and Windows Server 2012.
Microsoft’s Bill Fill explained in detail about this error in The Answers Forum. He starts with apology for the inconvenience caused by this issue and thanks the users for trying out the Release Preview. Further he says that Microsoft may contact a few of those who reported this issue if further info is needed as it may be a bug and has to be corrected before RTM.
Then he describes what exactly has changed since CP as users who could run the CP on their machine encountered this issue while installing RP on the same machine.