If you have multiple partitions on your computer with different operating systems installed then you can change the active partition in Windows so that when your computer starts, it will load the right operating system, we called dual boot. If you are thinking of doing this, then only change that partition in which the operating system is installed. otherwise, your computer will not work.

Before activating any partition, be careful about these things :

Logical drives and extended drive should not be marked as active. Only the primary partition can be converted into active. There should be a single active partition on a hard disk.

if you have more than one hard drive, then you can mark a partition as active on each disk. But your computer BIOS selects your first hard disk on startup, which you can change in the BIOS.

Set Active Partition via Disk Management

to set an active partition. first, you need to open disk management by search diskmgmt.msc on the start menu.

you will see all partition here, Right-click on the primary partition that you want to mark as active and choose Mark Partition as Active.

If you make a mistake, due to which if your computer is not starting and you want to activate the partition, then you can also activate the partition from the command line.

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to do that first open your computer in safe mode, once you there, go to troubleshoot then advanced option and click on command prompt.

type diskpart at the prompt to get boot up disk list.

at diskpart prompt, type list disk. now you will get all disk that attached to your computer. Now type select disk n here n is your current disk number.

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once you select your current disk. type list partition to get a list of all partition on that disk. to active partition first, you need to select that partition. Type in select partition n, where n is the partition number.

Now, we have selected the disk and partition, we can mark it as active by just typing the word active and hit Enter. That’s it! Now the partition is set.