Active Partition

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What is an active partition? What’s the difference between active and primary partition?

What is Active Partition?

Active Partition is the partition that contains the boot files for the operating system you want to run, that is, the partition from which the computer starts up.

Only one partition on each hard drive can be set as an active partition or bootable partition.

Active Partition
Active Partition – Windows 10

Alpha-based computers have no active partitions; these are configured by the manufacturer-supplied configuration program.

How to Set Active Partition on Windows

Windows Server, Windows 10, and other Windows Systems can share steps as follow to set active partition:

  • Press shortcut key WIN+R to open RUN box, type diskmgmt.msc, or you can just right-click on Start bottom and select Disk Management in Windows 10 and Windows Server 2008
  • Right-click on the partition you want to set active, choose Mark partition as active

Difference Between Active and Primary Partition

You can have up to four primary partitions, also known as “volumes,” on a hard drive. Changing them is risky and can make files inaccessible or render your computer inoperable.


During OS installation, Windows creates one primary partition that encompasses the entire disk. However, you may create up to four primary partitions. If you want more than one OS on your computer–known as a multi-boot system–you must create one primary partition for each OS. You can also use additional partitions to organize, separate and store data files. Doing so often improves system performance, and it can come in handy if the OS ever becomes corrupted, unbootable or infected with viruses.


Whichever primary partition from which you load your OS at boot time becomes the active partition. You can designate only one partition active at a time. If you have a multi-boot system, you already know this fact indirectly, as switching from one OS to another requires that you reboot the computer. When you make your OS selection at boot time, you mark that specific operating system’s partition as active.

If you’re only running one OS, your “C” partition, or “C” drive, should remain permanently active. If you accidentally mark a partition as active that doesn’t contain, your system won’t boot. Therefore, the “C” partition in a single-boot system is both primary and active. In a multi-boot system, the active partition changes when you load another OS.