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Windows 7: Windows cannot delete active partition

22 Sep 2010   #1

Windows 7 Home Premium 32 bit
Windows cannot delete active partition

Okay, so last night I decided to do a fresh install on my desktop of Windows 7 Home Premium 32bit. I have 2 hard drives, an old 120GB (C:) and a new 1TB (F:). The prior install of Windows 7 was on my C: drive, and so I installed the fresh install on F:. The reason I did this was because I was getting tired of having to redirect my installs to F: every time I installed something new.

My plan was to use my C: drive as a drive for media (pictures, music, docs, etc. etc.) and use my F: drive for installs like games, software, etc. Had I thought about it more, I probably would've caught my mistake right away, but I didn't. When I opened up disk manager after the install to wipe the C: partition clean, I got "Windows cannot delete the active system partition on this disk."

Is there a way to counter this, so I don't have a "ghost" install of Windows 7 on my C: disk? Or did I screw myself out of 120GB of HD space?


My System SpecsSystem Spec
22 Sep 2010   #2

Microsoft Community Contributor Award Recipient

Windows 7 64 Bit Home Premium SP1

Hello radioempty. Welcome to the forum.

In the future, disconnect the C: drive, or any drives other than the install drive and then install the OS. This will avoid your problem, and some others you can have.

What has probably happened is that Windows install saw that there was an Active partition already installed on the computer. Regardless of what Drive letter, or what additional disk you install the "new" OS to, the Master Boot Record for both OS's will be saved on the existing Active partition.

If you now disconnected the C: drive the computer will not boot because there is no MBR. You could disconnect the C: drive and then try this method to rebuild the MBR on F:: Startup Repair - Run 3 Separate Times

Once you get your new install to boot you would then need to work on cleaning up the old C: drive for data use. But that is another thread!

Good Luck.
My System SpecsSystem Spec
22 Sep 2010   #3
Microsoft MVP


Please post back a screenshot of your full Disk management drive map and listings, using Snipping Tool in Start Menu - attach file using paper clip in reply box.

We can then give you the commands to use to move the System MBR to F and deactivate C so that you can format it.
My System SpecsSystem Spec

22 Sep 2010   #4


If you want to delete a partition flagged as active, you have to boot to an environment that allows you to dismount the HDD(as in from a CD/DVD or USB flash drive).. this tutorial will provide you with an easy means of doing that
My System SpecsSystem Spec
22 Sep 2010   #5

Windows 7 Ultimate x64 SP1

Hey, guys, instead of doing the 3 time repair disk deal wouldn't it be easier to use EasyBCD to move the MBR to another partition (or disk) and then make it the Active partition (or disk)?

Windows cannot delete active partition-screenshot_3.jpg

My System SpecsSystem Spec

 Windows cannot delete active partition

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