Windows 11 KB5043145 update causes reboot loops, blue screens

​Microsoft warns that some Windows 11 systems enter reboot loops or might freeze with blue screens after installing the September 2024 KB5043145  preview update.

This month's KB5043145 optional update was released on Thursday with fixes for multiple issues, including Edge and task manager freezes.

One day after this cumulative update rolled out, Redmond added a new known issue to the KB5043145 support document on Friday, confirming that Windows 11 22H2 and 23H2 users might see their computers enter restart loops and, in some cases, become unresponsive.

"After installing this update, some customers have reported that their device restarts multiple times or becomes unresponsive with blue or green screens," Microsoft said.

"According to the reports, some devices automatically open the Automatic Repair tool after repeated restart attempts. In some cases, BitLocker recovery can also be triggered."

The Automatic Repair tool included with the Windows Recovery Environment is a Windows feature that will open automatically on systems experiencing common issues, such as errors, problems, or crashes, to diagnose and repair Windows installations that can't boot correctly.

In a separate entry on the Windows health dashboard, Microsoft also urged customers experiencing boot issues after installing the KB5043145 preview update to file a report using the Feedback Hub to provide more details.

Working on a fix, more recent boot issues

"We are currently investigating this issue. We will provide an update when more information is available," the company added.

Microsoft also resolved a known issue in August that caused boot problems and freezes on Windows Server 2019 systems.

Redmond's engineers are also fixing another bug that triggers Linux booting issues on dual-boot systems with Secure Boot enabled. Both of these known issues were introduced by the August 2024 Windows security updates.

Also, in August, Microsoft fixed a bug in the July 2024 Windows security updates that was causing some Windows devices to boot into BitLocker recovery.

One month before, it addressed another known issue introduced by the June 2024 KB5039302 preview update, which triggered restart loops and taskbar problems on Windows 11 systems.