Windows 7 Forums
Welcome to Windows 7 Forums. Our forum is dedicated to helping you find support and solutions for any problems regarding your Windows 7 PC be it Dell, HP, Acer, Asus or a custom build. We also provide an extensive Windows 7 tutorial section that covers a wide range of tips and tricks.

Windows 7: How to switch/rename boot partition to keep it as C: different drive

26 Jul 2014   #1

Windows 7 Ultimate x64
How to switch/rename boot partition to keep it as C: different drive

Long Story short I got a laptop with an HDD where I originally installed windows 7 (on C:).
I purchased an mSata SSD drive and cloned the HDD to the mSata as I would like to use it for OS and most used programs (for obvious performance reasons).

Now I got:
Boot set to Disk0 Partition C:\ (HDD)
and a clone of the C:\ partition labelled X:\ (mSata)

What I would like to do:
- Boot on the mSata (currently X:\)
- Ideally rename X:\ to C:\ and rename C:\ to anything (or just format it once Im sure everything is good).

What I did/tried:
I have read several threads about similar operations but none is matching my case as I am having a clone copy with a different letter and would basically "just" need to rename the drive letter and change the boot.

In Bios I have set it to boot to the mSata drive in priority but it appears to keep booting on C:\.
It douns quite simple but ends up being quite complicated.

edit: post #3 seems to have worked: Changing Win7 System/Boot Partition without Reinstall

My System SpecsSystem Spec
26 Jul 2014   #2
Microsoft MVP


Post back a screenshot of Disk Management - Post a Screen Capture Image.

Win7 should always boot up as C drive no matter which one you're booting in a Dual Boot like that. If not I'd clone it again this time using the Auto drive letter setting, carrying over the Active partition (System Reserved?) on the source HD, MBR and Track 0 if those choices are offered. Then all you need to do is change the HD set to boot first in BIOS to start up the clone and it should boot as C.

If not let us know what options are available for cloning, and let us see the screenshot of both drives now preferably booted into the new OS if possible.
My System SpecsSystem Spec
26 Jul 2014   #3

Windows 7 Pro x64 Windows 10 Pro x64

Even if it was X, which it shouldn`t be as Greg has stated, you just can`t change an install partition letter, it would render your system useless
My System SpecsSystem Spec

26 Jul 2014   #4

Microsoft Community Contributor Award Recipient

Vista x64 / 7 X64

He hasn't changed the os registry letter. It is a clone.

Looks like he has fixed it:
My System SpecsSystem Spec
27 Jul 2014   #5

Windows 7 Pro 64 bit

How drive letters work:

Partitions themselves have no concept of drive letters. Nowhere in the partition is there anything that specifies what drive letter it is. Back in the days of DOS when partitions were first devised drive letters were assigned by a fixed set of rules. A drive letter was what it was and there was no way to change it directly. This was simple but had some drawbacks. A big one being that installing a new physical drive could change existing drive letters and there really was nothing much you could do about it.

That changed in NT. Drive letters are assigned in the registry. When you set drive letters in Disk Manager that is what it is doing.
My System SpecsSystem Spec
27 Jul 2014   #6

Windows 7 Ultimate x64

Indeed, C: and X: were 2 clones. I applied the commands given in the link mentionned and it made my X: become C: and vice versa.
Anyway my laptop has then booted from the mSata drive which was my goal and I formatted the HDD to use it as secondary drive.
My System SpecsSystem Spec
27 Jul 2014   #7
Microsoft MVP


Those instructions you followed make the clone bootable on its own so when you set it first to boot in BIOS it will boot. It was already cloned as C but only seen as X in the old OS"s Disk Mgmt or WinRE. As Brian pointed out you can't change an OS letter once assigned without ruining it.

It would still be good to see the Disk Mgmt as I'd requested since about half the time we spot something awry.
My System SpecsSystem Spec
28 Jul 2014   #8

Windows 7 Ultimate x64

That's how it is now , note that I have formatted the "new" X: and renamed it to G:
My System SpecsSystem Spec
28 Jul 2014   #9

Windows 7 Pro x64 Windows 10 Pro x64

Looks Good, I didn`t even know I could read French

oui oui misure
My System SpecsSystem Spec
28 Jul 2014   #10
Microsoft MVP


Looks OK, but be aware that you must unplug the other hard drive whenever you do a reinstall or Startup Repair or it may derail the System partition to the first Primary partition in order.

For this reason its best to have the OS in DISK0 position, by swapping the cables and resetting it first to boot in BIOS, if possible.
My System SpecsSystem Spec

 How to switch/rename boot partition to keep it as C: different drive

Thread Tools

Similar help and support threads
Thread Forum
Partition Manager. Primary Boot Partition as Secondary Drive.
I loaded a hard disk formatted as a Windows Primary Disk onto my SATA controller. The BIOS sees the disk. In this case I want to load the new disk as a secondary drive (of course I have booted with a different hard disk). I load the Partition Manager and inside I find that the partition manger does...
Hardware & Devices
How to move a HDD partition over to your (C:) drive (boot drive)
Hi all, I think I might be posting this in the wrong section, but I didnt see anything related to Hard Drives for sections, so I thought I'd post it here. Sorry if it's incorrect. Anyways, onto the problem. So I bought my laptop, and its an ASUS G55V, with a 750GB HDD. Unfortunately, it...
General Discussion
win7 sp1 switch my boot drive...
Hello, I want to know, i what happened to me today, if it's happened to someone else too. Yesterday, i installed win7 service pack 1, the installation goes well and have a message that sp1 was succesfully install. Today, i turn on my computer, and i realize that my desktop was my old...
Windows Updates & Activation
Boot partition only installs on 2nd drive
Hi, I've read all about, and understand what the 100mb boot partition is, why windows 7 creates it etc. However my issue is that Windows only wants to create it on Disk1 i.e. the second drive, and not on Disk0 along with the OS. I don't want Windows on Disk1 because my motherboard see it as the...
Installation & Setup
rename OS partition
to rename a partition that contains an OS in XP you would goto start up and recovery there you could change the name of the OS but that option seems to have moved, where has it moved to? thanks
General Discussion

Our Sites

Site Links

About Us

Find Us

Windows 7 Forums is an independent web site and has not been authorized, sponsored, or otherwise approved by Microsoft Corporation. "Windows 7" and related materials are trademarks of Microsoft Corp.

Designer Media Ltd

All times are GMT -5. The time now is 09:23.
Twitter Facebook Google+