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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).

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3 Answers 3

The 8MB is reserved for dynamic disk conversion

http://support.microsoft.com/default.aspx?scid=kb;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.

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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.

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

More information on WinRE: http://en.wikipedia.org/wiki/Windows_Recovery_Environment

Information on Bitlocker: http://social.technet.microsoft.com/Forums/en-US/w7itproinstall/thread/31d88a3b-a464-45ec-ad31-36961ecae256

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.

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