active
On basic disks, marks the partition with focus as active. Only partitions can be marked as active. A partition must be selected for this operation to succeed. Use the select partition command to select a partition and shift the focus to it.
Caution
DiskPart only 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, and is capable of containing the operating system startup files. DiskPart does not check the contents of the partition. If you mistakenly mark a partition as active and it does not contain the operating system startup files, your computer might not start.
Syntax
active
Examples
To mark the partition with focus as the active partition, type:
active