Change drive letter for system drive

**Arlo1** · 13-02-2009

I had just added a new hard drive on my pc. I am having a old sata drive on my pc which is having windows installed on it. Now after adding the new hard disk windows assigned it as letter I. I want to change that. I want it to use it for backup. I tried to do the same through disk manager but got error on the screen. I am not able to understand the problem behind the same. I thought it will be simple to rename the same and change the drive letter. But it fails to work properly.

**Billie** · 13-02-2009

What error you are facing. Can you post that completely here. If you are getting error related to access denied or unable to assign a drive letter then it is recommended that you use windows disc to format the drive and create new partition. That is the best way of formatting drive. I think your system is having some kind of permission issue due to which you are not able to format the partition. Just try windows disc and then check back.

**Chapal** · 13-02-2009

What error you are facing. There are some third party partition manager software which works really fine with formatting and fixing such kind of problem. It is extremely simple to use. Just download those tools and then install them in your pc. You can then format the partition or resize as needed. It is extremely simple I think. I am using Easeus here. It is a nice portable tool for configuring the partition size with less errors.

**techman** · 13-02-2009

The issue that you are facing is due to permission issue. I will advice you to do the same in admin account. The drive letter is assigned automatically by windows. There can be a optical or usb drive which is already occupying old drive letters due to which it is assigned as I. I will recommend you to backup your data first and go with clean installation. That will be more better. Then use the windows installation disc to create new partitions as per your need.

**JUSTICE** · 14-02-2009

Try Paragon Partition Manager. I am sure this is one of the best tool to fix the issue you are facing. You can download it and install the same from web and use it for fixing your partition issue. You can also try cmd command line to fix the issue. But it can only allow you to reformat the partition. While if you go with clean setup like using the windows disc as mentioned above and format your pc by arranging the partition then it will be more easier for you to fix the problem.

**gachiman** · 12-06-2009

Switching your system volume from any other letter to C is doable. It's definately not for the feint of heart and you could easily destroy your installation if you are not careful. It probably is better in the long run to backup all your data and reinstall windows and reinstall all of your additional software.

You can change the drive letter in windows xp with administrator rights in the registry. Most of the critical windows functions boot from device ID rather than drive letter. The device ID will stay the same no matter what letter your drive is named. Windows should boot up in a very limited state, but be aware that 99% of all the software installed will not be accesable as well as a lot of windows functions immediately after reassigning the letter. The big problem you face is to do a sweeping change of thousands of entries in your registry to point to the newly assigned drive letter. There are free utilities out there to do this (windows does not provide a search and replace for your registry), although I don't remember exactly which one I used when I was in a similar situation to you. Try Googling Windows xp registry search and replace. You will need to download one or more of these programs to your desktop before you do anything since you will not have internet access after you switch drive letters and explorer will most likely crash your system trying to browse anywhere other than your desktop. Do not install any of these programs before you reassign drive letter either or they will most likely not run.

Once you have a registry search and replace application downloaded to your desktop, log into windows as an adminstrator.

go to start > run
type in regedit, then hit enter

Browse to registry key HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

Look in the right panel and you'll see entries like \DosDevices\I:

find the one associated with your current system volume, then right-click it and rename it to \DosDevices\C:

If there is already an entry for \DosDevices\C: you'll need to rename it to an unused letter first. If it's just a removable drive, then it's really not a big issue.

close regedit and reboot your machine.

If all goes well you will get back your desktop after reboot. You'll probably get a lot of error messages. Don't worry about those right now, just close all warnings.

You should now install one of the utilities that you downloaded to your desktop to find and replace registry entries. then launch the program after installation

do a search for I:\ and replace all with C:\ (provided I:\ was your old system volume letter). Once it has completed, reboot your machine again. You should have a very stable version of windows with 99% of all your applications and windows utilities running. A few applications will probably prompt you with a grey box looking for a particular file. If you look at the beginning of the string you will see it is probably looking for it in I:\path\to\wherever\the\file\is\installed Simply change the I to C and leave the rest of the path intact and tell it OK. It should find what it was looking for an resume to run as intended.