Windows August update plays Blue Screen bingo – and MSI boards got the winning ticket

BIOS update issued with tweaked Intel microcode

There's good news for those suffering from a dreaded UNSUPPORTED_PROCESSOR Blue Screen Of Death screen following the installation of August's Windows update.

The error condition was experienced by some users following the installation of either the KB5029351 and KB5029332 Windows 11 updates or the KB5029331 Windows 10 update, according to hardware maker MSI.

The motherboard biz quietly released a BIOS update aimed at users of the MSI's Intel 700 and 600 series motherboards, paired with Intel's 13th-gen Core i9 chips, which will stop the exception being thrown.

At the heart of the matter was a microcode update recently issued by Intel to hardware makers including MSI, which then distributed that microcode to users in the form of BIOS updates. That microcode-BIOS update clashed with Microsoft's OS update, leading to the BSODs. Now Intel has tweaked its microcode and handed it to MSI and others to distribute so that the Windows patches no longer break, hence the latest BIOS update from MSI.

The processor maker noted this week:

Intel is aware of reports from end users of blue-screen hangs with error code “Unsupported Processor” when updating to August 2023 preview Updates for Microsoft Windows 10 and Windows 11 while using the latest BIOS updates from system manufacturers on affected processors.

Intel has identified an issue in recent microcode updates to system manufacturers which can cause this error code.

As of September, Intel has released updated microcode versions 0x11D and 0x411C to system manufacturers to address this issue on 13th Generation Intel Core Processors with Performance Hybrid Architecture.

If you have any of the affected Intel processors, regardless of your motherboard maker, you should check to see if a BIOS update is available to install to avoid any similar trouble.

Microsoft admitted it was aware of the BSOD crashes shortly after it emitted its updates. Some Windows users found their PCs tripping into a Blue Screen Of Death following installation.

The Windows giant said it was looking into the issue, and later said the problem was not caused by any bugs or faults in its code. Instead, it was a screw-up limited to a specific subset of processors and hardware. As such, the Windows giant pulled the update for customers using the affected kit.

Those unlucky enough to already experience the BSOD found Windows was usually able to recover and roll back the patch.

At the time of writing, Microsoft has not revised its documentation to reflect the availability of the BIOS update.

MSI confirmed it was looking into the issue after it was reported, and yesterday issued a BIOS upgrade that it said would resolve the problem.

It blamed a firmware-level issue with Intel's silicon, and said the fix would include the updated microcode, "which will prevent any more messages regarding the 'UNSUPPORTED_PROCESSOR' issues." However, it did not go into any further detail regarding why the August Windows update experienced the problem.

It is entirely possible the issue was the result of Microsoft tightening up the processor checks within Windows and the microcode and/or BIOS reporting something that the operating system was not expecting, the result being the BSOD. We've asked Microsoft and MSI for more information and will update this piece if we get a response.

In the meantime, MSI said it planned to make the updates available for the Intel 700 and 600 series this week. It said: "All BIOS release [sic] will be available by the end of September." ®

Editor's note: This article was updated to include more information direct from Intel about the BIOS-microcode-level issue.