Partition - Mark as Active

How to Mark a Partition as Active in Windows 7​

Contents

• Mark as Active in Disk Management
• Mark as Active in Command Prompt
• Mark as Active in Partition Wizard

   Information

Marking a partition as active on a basic disk means that the computer will use the loader (an operating system tool) on that partition to start the operating system.


At various times the need to mark a partition as active arises. This will show you two ways of doing so.

   Note

• You must be logged on as an administrator to mark a partition as active.
• You can't make a logical drive or an extended partition active. Only a primary partition can be made active.
• There can be only one active partition per physical hard disk.
• If you have multiple hard disks installed on your computer, it's possible for each hard disk to have a partition set as active. However, the active partition on the first hard disk that your computer's BIOS detects is the one that will start the computer.

   Warning

Do not mark a partition as active if it doesn't contain the loader for an operating system. Doing so will make your computer unbootable.

If you disable the Disk Defragmenter service, then you will get the error below when you try to do anything in Disk Management. If you get this error, then make sure that the Disk Defragmenter service is set to only Manual.

METHOD ONE

Mark as Active in Disk Management

1. Type diskmgmt.msc into the start menu, and press enter.

2. Right click on the partition you want to mark as active, and select Mark Partition as Active.


That's it!

If you can't boot into Windows, use method 2.

METHOD TWO

Mark as Active in Command Prompt

1. Boot into your Windows 7 installation or repair disc.

   Tip

If you don't have a Windows 7 installation DVD, you can Create a Repair Disc.

2. When you get to the language screen, press Shift+F10.


3. Enter diskpart, then list disk after diskpart is loaded.


4. Enter select disk [number of the disk the partition is on].


5. Enter list partition, followed by select partition [partition number].


6. Type active.
There you go! You can now close the command prompt and reboot your computer.

   Tip

You can also use this method from within Windows. Type cmd into the start menu and press enter.

METHOD THREE

Mark as Active in Partition Wizard

1. Download a copy of the Partition Wizard Bootable CD.

2. Boot it up, right-click on the partition, and select Modify>Set Active.

Related Tutorials

---

• How to Mark a Partition as Inactive in Windows 7 and Vista
• Data Partition
• How to Delete a Partition or Volume in Windows 7
• How to Extend a Partition or Volume in Windows 7
• How to Create a New Partition or Volume in Windows 7
• How to Shrink a Partition or Volume in Windows 7

 

[Jonathan_King]

What are you trying to do here? I assume marking the partition as active is not your end goal; perhaps we can get to the root of the matter without worrying about a System label.

 

[herbun]

I am trying to install sp1 on a win7 home premium machine. The system partition should be active for updating, but since I could not do that yet, I do not know if that would resolve my sp1 update problem. See thread here:
http://www.sevenforums.com/windows-...sp1-update-problem-automount.html#post1937061

 

[armyjams]

THANK YOU GREGROCKER!!!

We use this tutorial many times every day to rescue Win7.

Greg, I would like to thank you from the bottom of my heart for having this link! What a life saver! My son's Dell Inspiron M5110 crashed and we could not get it to do anything but f12 and f2. I had the Official Dell Disk set, but even when reinstalling Windows 7, I would get "Missing Operating System" on restart! I was going crazy. I work on the laptop for hours on my own, then 5 hours with different Dell support to no avail! I did what you said above, the first time I got a command control screen on restart, whoops, wrong partition. I got back in using the windows disk, did what you said again but partitioned a different number. Walla! Bells and whistles, I got it to reinstall windows from scratch! My God's Blessing be upon you! Thank You!

 

[samarthya]

Thanks Guys!! the diskpart did it for me.

 

[shanemckiness]

Need help. Minitool partition wizard is not working. I get the option to select it after rebooting with a flash stick, but then when I select it, I get this message

error:/boot/bz/image3 has invalid signature
error: you need to load the kernel first

press any key to continue.

I need to active the mbr as I deactivated not knowing what I was doing, now the cpu will not start, end of story. PUtting a 2nd hard drive in will not work either since windows will not recognize the 2nd drive.

 

[Chuckamundo]

AHA...!!! Please correct me if i'me wrong on this hypothesis! I'me having issues with my dual os boot system when i unplug one of the os-drives. One has Win2k and the other is Win7. I wish to remove / unplug / wipe the Win2k BUT when i do this i get ‘Reboot and select proper boot device or insert boot media in selected boot device and press a key’. This STILL happens after i used the Win7 repair disk & command prompt & bootrec.exe /rebuildbcd /fixmbr /fixboot . This STILL happens after i wiped the Boot Manager menu & took Win2k off the boot list by using EasyBCD. Now, after this when I yank the Win2k drive i get the error 'Reboot and select yada yada' so, i looked in Disk Management and saw Win2k (System, Active, Primary Partition) and Win7 (Boot, Page File, Crash Dump, Primary Partition), so IS the "Active" causing the Win7 drive with "No-Active" to cause the ‘Reboot and select proper boot device or insert boot media in selected boot device and press a key’?

Thanks for any brainy replys, it's appreciated. ;}

 

[SIW2]

yes. Your win 7 disk needs an active partition and the boot critical files need to be on there.

If you remove the win2k disk first, then run startup repair from booted media (it might take 2 or 3 runs) that should do the job

 

[Chuckamundo]

yes. Your win 7 disk needs an active partition and the boot critical files need to be on there.

If you remove the win2k disk first, then run startup repair from booted media (it might take 2 or 3 runs) that should do the job

Ok, i did prior attempt to repair the Win7 with the retail CD, and after 3 tries it still was finding "something" (sorry, i'me a LOT MORE explicit and observant than that) so no joy there, but i WILL attempt the auto-repair again from the retail cd for a few tries once i set / mark the drive as "active" (YES, i DO understand only 1 partition can me marked AND needs to be basic NTSF and Simple (?))

The boot "files" (shown in the Disk Management window (with all the other drives) are on the Win7 drive so that's good, although i still can't understand "why" it was'nt set Active by / when i installed Win7. I'll give you the prognosis over the weekend, thank you thank you.

OH, almost forgot, i'll yank the Win2k after i put the Active on the Win7, and then boot from the CD.