[how to fix] when windows 7 can't see other partitions

Perris Calderon

Staff member
Political Access
24 Jan 2002
This is usually because you are dual booting two windows operating systems

before you start, backup your entire hardrive, I would create an image if you have the applications to do it.

No matter what letter you assign the partition for any windows it will see itself as the letter "c" once it mounts that operating system

for instance, if while in vista you format for dual boot and give the new partition the letter "e", install windows 7 to that "e" partition, once you boot windows 7 will think it's running on "c" even though it's really running on "e".

it does this so that writing programs is that much easier, programs won't get confused and can always be written for "c" regardless of which drive the OS is mounted

the workaround is simple;

from your NEW operating system, (NOT THE ONE ON THE REAL "C" DRIVE) paste "diskmgmt.msc" into run, with or without quotes.

in the applet you'll see the partition that windows 7 can't yet use, it will have no letter assigned since it can't see two "c" drives

highlight the drive that you know is your original windows install, right click and run through the wizard to assign a new letter, the OS will suggest the next available letter which should be fine, if you have a personal preference go right ahead and type it in

complete the wizard and that's it, the new letter is just referance for the new os, your original install will still see it's own partition as "c" when you boot

I must remind you again, you MUST do this from the NEW operating system NOT the original

if you want to play it safe the applet will also offer to mount the drive as an ntfs folder, while I haven't tried that yet it should work fine and be a safer procedure.


do not follow this sequence till you have SAFELY mounted both operating systems to insure you have not broken the startup sequence when you installed your dual boot

going to stick this thread till windows 7 goes live
Last edited:

if anyone has tried mounting the drive as an ntfs folder please post and tell us how that worked out
it does this so that writing programs is that much easier, programs won't get confused and can always be written for "c" regardless of which drive the OS is mounted
It does this because MS know all about writing bad code so they want to help others who write bad code also. ;)
perris: i know i'm kinda late to the game, but i think your theory is a touch flawed. I know back when Windows 7 (and i believe even Vista) were in Beta, a lot of times if you had two partitions, Windows wouldn't automatically assign a drive letter to it. That wasn't only because of dual booting. The Windows installation process does not see drive letters. This is why when you install, you'll only ever see something like "Disk 0 Partition 1" and such. It's the OS itself that designates it's own volume as drive C, and automatically labels each other drive/partition. I've already had three separate hard drives connected back then, only running one OS, and no matter what, one drive wouldn't be shown. When i disconnected the third drive and reinstalled Windows at a later date.... only one of the drives was shown, and not the other. It was just a bug during the installation.

.... sorry if you already knew this... just figured i'd post it anyway.

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