How to mark a partition as active on Windows or Unix

Tags: System Administration

All operating systems have the feature of marking partitions as active. I’ll provide helps for Windows, Linux and Unix (Solaris),


Using Windows XP to mark partitions

On Windows, we use the Windows Disk Management Tool to perform this,

  • Enter into disk management (click run from start menu and type diskmgmt.msc).
  • Right click the primary partition you want to mark as active.
  • Click Mark Partition as Active and it's done.

The new active partition used by the System BIOS during next reboot.

Using Windows Vista/Seven to mark partitions

Click "Start Menu -> Programs -> Accessories". Now right click on "Command Prompt" and rus as administrator. Now please type as following,

c:>  diskpart 
diskpart> select disk 0          // list command will list available disks 
diskpart> select partition 1     // list partition will list partitions 
diskpart> active                 // mark selected object as active 
diskpart> exit

You have to provide your own partition number instead of partition no. 1

If you are using Windows Vista be aware that Vista Boot Manager have bugs. It might behave unstable after changing active boot flags.

Using Linux to mark partitions

In Ubuntu/Fedora/Suse CD/DVD you have to use this command,

$ fdisk /dev/sdaX

where X = partition which you want to mark or unmark then use ‘a’ to modify active flag. Press w to store the modification upon completion.

How to mark another partition as active on Solaris

If you can boot into your Solaris OS, boot into Solaris System

Please enter following command to modify Solaris Root Partition,

# fdisk /dev/rdsk/c0d0p0

Depending on your disk configuration this can be c0d1p0 etc,

  • To select "Specify an active partition" please press 2.
  • You have to select the number of the partition you want to mark as active.
  • Afterwrds, please press 5 (to save changes and exit).

If you are using a Solaris DVD/CD or Solaris Live DVD or USB Boot you can still mark a partition as active from the console. First, boot into Solaris from the media. Then,

  • Select console
  • In console type the same commands we used previously with Solaris OS.


  1. How to Set or Mark a Partition as Active in Windows

No Comments

Add a Comment