Windows 10 users report blue screens of death after Patch Tuesday update

Some Windows 10 users are seeing a blue screen of death after installing an update on Patch Tuesday. Microsoft says it is investigating that signature validation issue.

The problem arises in cumulative update KB5021233 for Windows 10 versions 20H2 through the latest version 22H2. That update was sent earlier this month on Patch Tuesday, the monthly update cycle.

Users report that in some cases they see a blue screen of death. There doesn’t seem to be a pattern in which devices are affected. The BSODs are accompanied by error code 0xc000021a. According to Microsoft, the problem occurs because no signature validation is done between the hidparse.sys parsing library and drivers in the system32 folder.

Microsoft has not yet made a solution available. The company says it is working on a patch. It is not yet known when it will be ready. In the meantime, Microsoft has described a workaround that requires users to manually place hidparse.sys in the system32 folder via Recovery.