GPT, or GUID Partition Table, is a modern disk partitioning scheme used by UEFI-based systems, including many Windows machines. It replaces older MBR-style partitioning, supports larger disks, and can describe many partitions with unique identifiers. On Windows, GPT is often the layout behind the EFI System Partition, where boot files are stored.
GPT matters in cyber security because boot reliability is part of system integrity. If the partition map is damaged, altered, or sized poorly, Windows may fail to start or fail during updates that need to touch boot components. Attackers with low-level access may target GPT disks by tampering with boot partitions or persistence files, while defenders check partition layouts, protect boot paths with Secure Boot and full-disk encryption, and validate recovery settings during incident response and patching.