Drive letter with Windows changed!

May 1, 2007
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I have a MacBook Pro and have been running Windows XP Pro SP2 on it for some time, using BootCamp.
I also have the rEFIt boot manager. Windows has always shown its own Partition as C: (and obviously no others show up from Windows). I didn't add or change any partitions...its all exactly as Boot Camp made it. My Windows partition is FAT32 32GB.

I recently received an external hard drive and decided to install Linux Fedora Core 6 on it, with the external HD plugged in via USB. During the setup, I unticked my laptop's hard drive so that only my external hard drive was selected and then continued to make an ext3 partition for it (20GB). I also ticked the box to install the G....something or other bootloader on the selected hard disk, which was probably pointless.

Upon restarting, Linux didnt start...but this wasn't terrible. However, when loading into windows (from my laptop's hard disk) I got a BSoD saying Session Manager Error.

Using the Windows XP CD and choosing to install windows shows my hard drive config as:
C: Partition 1 [Unknown] 200MB (200MB free)
E: Partition 2 [Unknown] 62464MB (62464 free)
Unpartitioned space 128MB
F: Partition 3 [FAT32] 32604MB (11202 MB free)

I can also see that all my files are intact on F: using the recovery console.

So basically it looks like my windows partition is being assigned letter F: instead of letter C:
and this situation matches a possible cause for the "Session Manager" error.
The problem is, I really don't know how to change it back. :(

(I feel that this probably can't be fixed via windows and instead must be something to do with the whole EFI boot system which I have no experience with. I do have access to the rEFIt console (part of the boot loader I guess) and I have tried resetting all the drive mappings using something like "map -r" but this didnt seem to make any difference.)

EDIT: Just to add some findings after bobtomay's post...
Partition 3 should be labelled C: when you install windows (well, thats how boot camp does it I think and that is how I need it)
I also forgot to mention that i CAN boot into OS X and see all my files on my windows partition (as it is FAT32)


Retired Staff
Dec 22, 2006
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Texas, where else?
Your Mac's Specs
15" MBP '06 2.33 C2D 4GB 10.7; 13" MBA '14 1.8 i7 8GB 10.11; 21" iMac '13 2.9 i5 8GB 10.11; 6S
Sorry, don't know enough about Mac's to help in the situation.
It does look like your installations are probably OK and have an issue only with the boot manager. Someone should come along that can help get you back into OS X.

Don't need to worry about the windows drive letter. It will be C: once booted into XP. When booting from the disk, it is going to assign drive letters based on the position of the partitions on the drive. E: will be your OS X partition, F: your XP partition and am guessing C: is probably the boot partition, though I don't know if Mac's use a boot manager in this way.

Good luck.

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