what to do when your boot drive gets f:/’d

Something we frequently do at work is a full backup and reinstall: image the boot drive to one of our backup drives in rotation, wipe their drive and reinstall Windows, find drivers and programs, then plug the backup drive in and copy their stuff back.

Long story short, Windows made the backup drive C:, called its actual boot drive F:, and once our drive was removed, it hung at the “Welcome” screen. It’s like someone never wearing shoes again because they broke a shoelace once. Or something. It’s just so staggeringly dumb I can’t think of a decent analogy.

Fortunately, this is the 2nd google result for “changed drive letters”. Reproduced here mainly for my own reference, and so you can remember reading about a fix if you ever come across it:

  • Run regedit (Windows key + R, “regedit”, enter)
  • Go to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
  • Rename (not modify the value of) \DosDevices\C: to Z: or something
  • Rename the actual boot drive (say F:) to C:
  • Rename the other drive back to F: or whatever
  • Pray, reboot, and pray some more

It worked for me, and that computer’s back on someone’s desk being productive.

Update 4/2/2010: I’ve come up with a new solution to this problem that seems to work consistently. Click here to go to the new blog entry I wrote to announce and explain it.

2 Responses to “what to do when your boot drive gets f:/’d”

  1. Jeremy says:

    This is why I like the Unix filesystem better — the physical location of files are abstracted.

    e.g. program files are always in /bin, /usr/bin, and user files are in /home, etc. If you decide to physically move, say, /home to another drive, it doesn’t need to change location (e.g. from C:\Users to D:\Users) — it’s just transparent.

    Currently, my Windows XP has the only drive as drive H:. It doesn’t have a C: drive, because it’s not the first partition. Any USB or other removable media become drive C: when they’re plugged in. It’s quite annoying, because there are quite a few poor-quality self-extraction tools (cough NVIDIA) that default to C: and bomb out if it doesn’t exist. On the other hand, it could be more secure, because if my computer became a zombie, and the zombie master sent out a mass command deltree c:\ to all the infected computers, it would fail to execute on my machine. 🙂

  2. tim says:

    Yeah, it’s alright when you actually installed Windows to that drive letter (I’ve dualbooted with 98 on C: and XP on D: before), but when it changes itself later on things get broken. 🙁

    I’d love a unix-like hierarchy in Windows. At least as recently as XP if you have a network drive mapped to something like I:, and you’re up to H: already with local drives, plugging in a thumb drive or something won’t do anything – you have to manually remap the drive letter in Disk Manager before you can do anything with it.

    Apparently you can mount volumes in empty NTFS folders. If someone had too much spare time they could probably script Windows to mount things in C:/media/usb0/ etc…