Dual-Boot System Drive Assignments Question

bfollowell · 20 Jun 2023

I've had dual-boot systems setup in the past, but probably not in ten years or more. I know some things have changed and Windows has definitely become more friendly towards these setups. I have a question concerning drive letter assignments. My two different installs, both Windows 10 22H2, build 19045.3086, each have their respective OS drives setup as C. I'm assuming this is normal. From there, the drive letter assignments are all over the board with very little similarity between the two OSes. Everything seems to be working OK, so I'm assuming each drive can have different assignments between the two OSes. I just wanted to confirm before I start playing with drive assignments.

I'd like to have the two OS drives be C and D under their respective OSes, with all the other drives going up from there, but I want to reassign so that they're the same in both OSes, with E being E in both, F being F in both and so on.

Should I run into any issues when doing this?

Megahertz · 20 Jun 2023

I assume that each of your Win 10 are on different drives. Are them same type (Legacy - MBR or UEFI - GPT)?
Drive letters are assigned by the OS to the partitions.
The drive you boot from will have C: assigned. All other partitions can have any (or none) drive letters.

During POST launch the boot menu to choose witch drive to boot from.

SIW2 · 20 Jun 2023

drive letters are stored in os registry. they can be different in each os.

NavyLCDR · 21 Jun 2023

SIW2 said:

drive letters are stored in os registry. they can be different in each os.

And you can also change them as you wish. So yes, you can have the two Windows partitions always be C and D and you can change the rest of the drive letters to be the same in each OS.