The latest Windows 10 and Windows 11 updates are causing some PCs to display a blue screen with an “UNSUPPORTED_PROCESSOR” error.

Some users reported seeing the error after installing the latest update and rebooting their system. Microsoft has investigated and determined the issue is not with the updates directly, but with a small subset of processors.

Microsoft has received reports of an issue in which users are receiving an “UNSUPPORTED_PROCESSOR” error message on a blue screen after installing updates released on August 22, 2023 ( KB5029351) and then restarting their device. KB5029351 might automatically uninstall to allow Windows to start up as expected. If this occurs, we recommend that you do not attempt to reinstall KB5029351.

Next steps: After investigating these reports, we have found that the “UNSUPPORTED_PROCESSOR” error was not caused by issues in KB5029351 and is limited to a specific subset of processors. We are collaborating with device manufacturers (OEMs) and will temporarily mitigate this issue by not offering KB5029351 to Windows devices that might be affected by this issue. If you still experience this issue, please contact your device’s processor manufacturer.

Hopefully Microsoft and the relevant OEMs will have a permanent fix soon.