Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I was formatting one my comps to do testing. The first partition seems to be EFI or something that i shouldnt touch. When creating another partition window 7 has a 100 mb blank partition before its partition (which is then 3rd). Why? what is this for? with windows XP i can create a partition and IIRC sometimes i may have a blank partition at the end which is small (like 8mb).

Can someone explain why windows 7 likes to create the 100mb partition? and why other times i will have a tiny partition at the end (NOTE i only care about the 100mb before my main partition).

share|improve this question

The 100 MB partition you're seeing is used by Windows 7 for WinRE (Windows Recovery Environment) and BitLocker.

More information on WinRE:

Information on Bitlocker:

You can prevent it from being created during setup by following these instructions at WinMatrix - note, they talk about a 200 MB partition. Pre-RC1, Win7 used 200 MB, but as of RC1, the Windows team reduced it to 100. Alternatively, you can pre-format and partition the drive before installing Windows 7, and the recovery information will be placed in your installation drive.

share|improve this answer

The 8MB is reserved for dynamic disk conversion;en-us;225822

Not sure what the 100MB partition has to do with EFI, unless you're installing it with Bootcamp on a Mac, in which case there is a 100MB partition that is used for BIOS emulation I believe.

edit: With a Vanilla Win7 install I believe it puts the boot files there if it was previously unpartitioned. I can't find documentation from MS right now, but maybe someone else can.

share|improve this answer

If you don't like it, you can always partition manually using DISKPART or other utilities. You can bring up a command prompt to run DISKPART right in the Windows 7 setup environment by pressing Shift+F10.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.