Mixed up drive letters during XP setup


Hello there,

I'm in a tricky situation. I have 1 hard disk, divided into 6 partitions. I'd like to dual boot Vista and XP. The partitions look like this:

C: Vista
D: [I want to set up XP here.]

From E: to H: the partitions are logical and contain personal data. Vista is already on the first partition, and I'd like to put XP on the second one (D:smile:. Now the problem is, when the ugly blue XP install arrives to choosing from the partitions, I see this:

C: Vista
I: [The second partition which should be D:.]

The D:-G: range is the same as the E:-H: in the correct drive letter line-up. It's not temporary, only for the time of the install. XP installs on I: and I: stays in use as a system partition.
I have even tried to set the original D: active. Then I saw this in the XP setup:

I: Vista
C: [The second partition which should be D:.]

As you can see, I: and C: are changed, but nothing else happened. So I'd like to know if there's a workaround with this problem. I just want to see exactly that drive letter order during XP installation which I see in Vista or in any partitioning application. I know a problem like this might be caused by a connected zip drive or something else. I'm using a laptop which contains a card reader (it's empty of course) and there's a flash drive with an NVCACHE partition belonging to Intel, but XP setup sees it as a different HDD so it can't cause the problem, can it?

I'm waiting for any advices, thanks in advance.
Hi howaito, welcome to NST.
Don't go messing around with the "active" flag. That's telling the MBR where to find the boot sector containing the Vista bootloader.
You need to create the partitions and install Vista as you originally did, then with Vista booted, use disk management to set all the disk letters for your partitions, optical drives, flash drives, external HDD, cameras etc to whatever you want them to be.
That way, whenever you plug in a removable, it will always come up with the letter you've assigned.
If you don't specifically assign letters, the OS will not permanently link them with any particular device, just assign them in sequence when it needs another.
When you've got everything labelled as you want it, run the XP setup from inside Vista (don't boot the XP disk) and tell it not to overwrite your Vista partition, but to install in D.
When it's finished, you won't be able to boot Vista because XP's NTLDR will have replaced the Vista bootldr.
At that point, boot the Vista DVD again, and select "repair startup" and you should have a functioning dual-boot.
Use EasyBCD to tidy up and name your boot choices to something recognizable, and then boot XP and repeat all the letter assignations to match what you did in Vista.
Before you install any software on XP, remember that some (adobe reader for example) will insist on putting stuff in C:\program files\common files, even though you tell it you want the software on D:\.
This will cause unpredictable behaviour if the same software is also installed on Vista. XP will also destroy Vista's restore points.
So at this early stage, it would be a good idea to hide Vista from XP to protect system restore and to prevent cross-system software confusion.
Read the sticky thread in Ideas and Wishlists about HnS which will do the hiding for you.
Hello Terry60,

thanks for the answer, actually, everything you've mentioned was done before my post, system management, EasyBCD or messing around with the MBR are nothing new, the only thing I can't do from your advices is installing XP from within Vista. The autorun simply doesn't give me the chance to do so, the Install Windows XP link is grey and not clickable for some reason.

By the way, I've booted a lot of times Vista and XP together but never used them together for a long term, so huge thanks for the hiding suggestion, I'm gonna take care of it once I can make my XP setup work as it should. I wonder if it would be better to put XP on the first drive since Vista will virtually see its own partition C: so there's no problem with these hard coded apps, but the truth is at the moment the last solution will be a new Vista, I've just set it up with all the configuration and software I needed.

So, if you have any other ideas or a way to install my XP in Vista, I'd be pleased to hear them. :smile:
I had virtually the same setup as you
Created 5 partitions
Installed Vista in the 1st (C), named all the others
Installed XP in the second (booted from the XP CD). It called itself D and Vista C. I named all the others.
So I don't quite understand why yours decided on I:\
The advice I gave about running setup, comes from MS, but you're quite right; I just tried it and the install option is greyed out. I think perhaps it will only work that way if the older system is installed first (MS assuming that updating a new system with an older must be a mistake ? - their advice for dual booting is also old before new (avoids having to repair the bootloader))
That greyed out option, I think from reading the Install notes on the CD, would execute i386\winnt.exe from the XP CD, so you could try circumventing the "grey" by going directly to it.
Thanks again, you're very kind and helpful. :smile: Actually, I've tried to launch the setup as you said and the outcome is quite funny. There are three files to execute:

WINNT.EXE - This won't work on 32-bit versions of Windows.
WINNT32.EXE - This returns a compatibility issue, and there's no official online solution. You were right, Microsoft thinks that you're gonna update your Windows and there's no official possibility on their disks to set up their OS on another drive. Like it wouldn't be an option.
WINNT32.MSI - This one starts an installation but then its window disappears suddenly.

I've even tried to change compatibility mode under Properties, no success. It seems pointless. I guess the most clever thing will be a new install for Vista as well, this time starting with XP. I'll wait, however, for some time, maybe someone will read this and tell me why are those drive letters mixed.
I looked back through old posts to find where this was discussed before
where I posted the relevant MS Vista Help.
Reading it again, I don't know what they're refering to when they say use the Custom(advanced) option ?
Looking at your first post, I notice the absence of H:\ in the 2 later lists.
That makes me wonder what it thinks H:\ is, if it's skipping it and going to I:\
Whatever is causing that might explain why my almost identical setup used D:\ and yours won't.
It looks as if it skips H: and goes to I: because XP considers the CD drive H: when you are booting from the CD.

A change in the newer version of Vista is likely the culprit with a greyed out install link when you try to install XP within Vista. Microsoft only suggests installing the OSes from oldest to newest, so you might be right there Terry.

Honestly, I would install on I: anyway since you know it is the second partition that you want XP on. Vista should consider the partition D: again when you boot it and if you're lucky, XP well consider itself D: as well when booted.


Never mind... in your post above you stated that XP continued to use I: as its partition :frowning:

Wipe Vista from the drive, install XP on partition 1 C:, and then install Vista from within XP on drive D: (Partition 2) so that Vista doesn't consider itself drive C: and shift the letters for your partitions when you use Vista.
Last edited:
Thank you both for your support. I've solved the problem, even if it was the worst way for me to do so.

I've installed XP on the first partition, which means I formatted Vista's drive. Then, from my fresh XP, after putting every drive letter in the right order I started a second XP setup from within the first one. This way the textmode installation saw the letters in the logical order, from C: to H:, without I:. For some reason my pre-configured unattended setup didn't work this way but at least I had my XP on drive 2, using the letter D:. After this, I simply booted from the Vista disk and installed it on the first drive. Now I'll need to use EasyBCD and that HnS tool Terry has mentioned above, then it's done.

It's a pity Linux doesn't offer the compatibility for my needs, I'd love to switch for good.
Glad you've got what you want.
If you'd left XP as C and run Vista setup from XP and let Vista be D, you'd have had the problem of needing to hide XP from Vista (because it would se a C:\ drive to confuse it), as well as Vista from XP (restore points)
But because of your persistence, with Vista as C and XP as D, HnS should be the perfect solution for you.
(Happily Guru has just sorted a niggling problem which affected a few of us, so you timed it perfectly)
Not part of the actual topic but the end of the story: after having a known but apparently still unsolved boot issue with acpitabl.dat I just decided not to mess anymore with XP and I've put Vista on both C: and D:. I can only hope that stepping towards Vista is a step forward. :tongueout:
Hope it works out for you.
I use Vista (x64) nearly all the time, but there are still some things it can't or won't do, which is why I keep a copy of XP (x86) in a separate partition. (It also enabled me to install some legacy software (16 bit installer) on XP and execute it from Vista, when Vista couldn't get past the 16bit installer)
Don't know if this is any use regarding your acpitabl problem
Last edited: