Microsoft is still in the process of implementing Intel’s security updates for the Spectre microprocessor flaw. However, one of the company’s existing patches seems to be causing problems for Windows 10 users.

The patch in the spotlight is KB4100347, which was sent out to users last month as a Spectre mitigation for Windows 10 April 2018 Update.

On Windows Update, Microsoft describes the Intel patch as:

“Intel recently announced that they have completed their validations and started to release microcode for recent CPU platforms related to Spectre Variant 2 (CVE 2017-5715 ["Branch Target Injection”]). This update includes microcode updates from Intel for the following CPUs”

Users are reporting the update is causing booting problems in machines after it is installed. The problem seems to stem from Microsoft sending out the patch to wrong Windows 10 builds. Some PCs that are not meant to receive KB4100347 are getting it.

Some users running an AMD-powered machine say the Intel patch is coming to them, causing problems. Others with Intel PCs say their particular processor is not supported by the patch. It seems uninstalling the update will fix the problems, which can be done through:

Start> Settings> Update and Security> Windows Update> View update history> Uninstall updates

While this will solve the problem once it occurs, it will not prevent the update downloading on machines it doesn’t support. Microsoft has yet to acknowledge this targeting problem, but we guess the company will have a fix soon.

Recent Mitigation

This news comes just a week after Microsoft continued to roll out new Intel patches to prevent Spectre attacks.

Specifically, Microsoft has sent out mitigation for several Windows versions. KB4346085 for Win10 version 1709 (Fall Creators Update), KB4346086 for version 1703 (Creators Update), KB4346087 for version 1607 (Anniversary Update), and KB4346088 for version 1507. Additionally, Microsoft also launched KB4346084 for the current Windows 10 April 2018 Update (version 1803).