How to Change Active Partition in Windows 7

How to Change Active Partition in Windows 7 - Upon purposely changing the active partition on my system drive, I was faced with a BOOTMGR is missing error during my system's start up that prevent Windows from starting. It is a common mistake to make when playing with partitions on a system drive and it can be a headache to solve if not prepared. To change your active partition back using the Windows 7 recovery disc or Installation DVD, follow the steps below :

1. Follow steps one to four in the above guide. This should take you to the Command Prompt in the Windows Recovery Environment.
2. Type DiskPart and then press Enter.
3. Type List Disk now and then press Enter. This command will list all disks attached to your computer and assign them a disk number.
4. Type Select Disk x, where x is the number for the disk containing the partition you wish to make active. Press Enter.
5. Type List Partition and then press Enter. You will now be shown a list of the partitions on the selected disk. Determine which partition you wish to make active.
6. Type Select Partition x, where x is the number of the partition you wish to make active.
7. Now, just type Active and then press Enter. That should be it - the selected partition is now active.

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