Active
DiskPart
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Syntax - active
On basic disks, marks the partition with focus as active. This informs the basic input/output system (BIOS) or Extensible Firmware Interface (EFI) that the partition or volume is a valid system partition or system volume.
Only partitions can be marked as "active."
Important
DiskPart verifies that only the partition
is capable of containing an operating system's startup files.
DiskPart does not check the contents of the partition. If you mark a
partition as "active" and it does not contain the operating system's
startup files, your computer might not start.