Microsoft has reported that two recent updates for Windows 11 24H2, specifically the April cumulative update KB5055523 and the March preview update KB5053656, are causing blue screen crashes with the error code 0x18B (SECUREKERNELERROR) after installation and reboot. There is currently no permanent solution, but Microsoft is working on a workaround using a Known Issue Rollback (KIR) that will automatically apply to personal or unmanaged devices through Windows Update. IT departments will need to manually download a Group Policy .msi file to implement the rollback. Affected machines will require a restart to complete the process.