Windows 10: New Win 10 install doesn't remap OS parittion to C:

I'm not sure how this happened, but I created a dual boot of Windows 7 and 10. When I installed 10 on a second partition (MBR, not EFI) Windows 10 does not remap it's OS partition to C: but stays on E:

This is causing a lot of problems because I need to install various home-grown installation tools that assume the OS runs on C: and has hard coded paths to look for things. (Yes, I know they're poorly written, I don't have control over them).

It's more or less impossible to change the partition letter after Windows has been installed (too many registry entries that have the paths wired in), but How can I ensure that when I do a custom install of Windows 10 to the second partition that it considers the partition to be C:?

:)

 

Windows 10 - BOOTMGR image is corrupt.

I found a Win 7 DVD and was able to install it. It's not right though. It can't find my WiFi and it thinks it is dual boot. Win 7 and 10. 10 doesn't work.

While I was trying to install Win 7, I found I had 3 drives (partitions).

C: 20 G labeled Recovery

D: 320G labeled OS

X: 31M labeled Boot

After Win 7 was installed the C: drive was 446 G and labeled OS and the D: drive was 20 G labeled Recovery.

I probably try to reload Win 10 from the USB drive

 

Installing Windows 10 on multi-boot system.

> Many programs are designed to be installed to C

None of the programs I've used since the days of Windows 98 required installing to C, including Office, Visual Studio, ... . I do have some
programs that install some or all content to the same partition as the currently running OS, while most programs allow most or all content to be installed on any partition. I don't have any programs that force an install to C.

That doesn't mean that there aren't a lot of programs that require install to C, it's just that I'm not using any of them.

Win NT, Win 95, Win 98, Win Me, Win 2000, Win XP, ... to Win 7 all have the option to install to any partition and without changing the OS partition to C . In the case of Win 7, the install needs to be started from XP or XP 64 (for Win 7 64 bit) to do
this. Win 10 is the first Windows that apparently doesn't offer this option. My guess is that it's just an install issue and that Win 10 could run from any partition, any letter, if it wasn't for the install restriction.

The other issue is that I boot into Win 7, install the Win 10 cd-rom, run setup, and off it goes copying files, without any dialog to ask if I want to do clean install or upgrade. Maybe it gets there eventually, but I aborted it after several passes. I'll
try the USB version later to see if that helps.

The USB utility was another issue, I had to run diskpart and then clean to clear out the USB MBR, otherwise, the USB image create utility would fail.

So back to the other guy asking about this, so far it doesn't seem that Win 10 can be installed without it relettering it's partition to C. It doesn't effect the partition letters seen by other OS'es when you multi-boot into them. I'm wondering how the image
backup from Win 10 describes the boot partition when it doesn't have a letter.

 

Leave the space where you want to install Windows 10 to unallocated (delete the partition there). Install to the unallocated space and let Windows 10 setup create the partition.

 

I'm fairly certain that's what I did, but I can't remember. So I'll try again.

Thanks for the advice.

 

So, I ended up going a different route. I wiped my Windows 10 install, made an image of my Windows 7 system with Macrium Reflect. Then I wiped the disk, installed Windows 10 in UEFI mode (with legacy csm support), then I converted my image to a VHD, then added a boot entry for it...

Nice, easy dual boot. The Win 7 seems a little slower, but that's ok.