It seems that Linux users are reporting problems with dual boot systems following Microsoft Windows monthly update, with some users reporting a message “Something has gone seriously wrong.”

So far Microsoft hasn't commented much beyond what's already known.

Tuesday’s update left dual-boot devices—meaning those configured to run both Windows and Linux—no longer able to boot into the latter when Secure Boot was enforced. When users tried to load Linux, they received the message: “Verifying shim SBAT data failed: Security Policy Violation. Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation.” Almost immediately support and discussion forums lit up with ​​reports of the failure.

[arstechnica.com...]