Microsoft’s latest monthly security update is wreaking havoc on dual-boot Windows and Linux systems. The software giant issued a security patch last week to fix a two-year-old vulnerability in the GRUB open-source boot loader used by lots of Linux devices. Microsoft’s patch wasn’t supposed to hit dual-boot devices, but many have found it has and it’s now stopping their Linux installs from booting properly.

Ars Technica reports that multiple Linux dual-boot users are seeing “security…