It seems that a hard drive is limited to 4 primary partitions, so if the 4 primary partitions are

  • Vista,
  • Recovery data,
  • Windows 7,
  • Windows 7 64-bit

and no more primary partition can be added and so no more OS can be installed?

Since an extended partition can install Windows 7 too, so what about just have 1 primary partition subdivided into 10 extended partitions, and so we can install many OS'es on it.

For example, if the machine comes with 1 primary for OS and 1 primary for recovery, then create 1 more primary and then 10 extended for data or for future OS installation.

Are there OS that cannot be installed on an extended partition? What about speed, would there be any noticeable slow down if an OS is in an extended partition?

  • 1
    an extended partition is just a special primary partition, so it's one of the 4 primaries, and you can only have 1 extended. the extended partition contains one or more logical partitions but the extended partition itself cannot contain a filesystem. (it would just be a plain old primary partition.) – quack quixote Feb 19 '10 at 2:24

You can use more than 4 primary partitions, if you hide the extra partitions.

For this game of hiding and unhiding partitions, you need a boot manager.
Some Linux distributions replace the Windows boot manager with another that doesn't suffer from that limitation, although this should be undertaken with great precaution.

The other way to go is to use a product that takes care of the whole thing. Some such products are :

BootIt NG ($34.95)
Support of over 200 primary partitions (if desired). I've used it and it's one of the best.

GAG (initials, in spanish, of Graphical Boot Manager) (open-source)
Allows boot of up to 9 different operating systems installed in primary and extended partitions. Never used it.

Partition Commander 11 ($49.95)
No info on maximum partitions number. I've used it a long time ago and it worked then pretty well.

Norton PartitionMagic 8.0 ($69.95)
Otherwise called BootMagic, no info on maximum partitions number, and seems to only support partitions up to 300GB. Never used it, and I usually stay away from Norton products.

Warning: Before playing with partitions, take great care with your backups.


Four primary partitions is a limit only with MBR partition table.

If you use GUID partition table, you don't have such limit.


I am not sure that you can install Windows 7 on extended partition, however, you can always make virtual disk file (*.vhd) on one of your current partitions, install Windows 7 into it, and boot from there.

Only prerequisite is to have NTFS partition with enough free space.


I'm not certain when Microsoft started to allow the installation of Windows on an extended partition--I'm 99% sure it was still disallowed in XP and haven't tried on Vista.

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