Arch Linux

potuz

Member

Registered: 2009-10-23

Posts: 129

installing windows on a pre-existing partition

Hi, I figured it would be faster to ask here. I haven't used Windows since 3.1 about 30 years ago. I am forced to install now on my system and am a little overwhelmed by the wiki page as it seems that most that I can find is about how to install linux on a system that already has windows. I have Arch installed in a GPT disk booting in UEFI mode. I have two disks, both GPT. Booting currently from Disk 2. Disk 1 is the one that has some free space. I understand that Windows 10 supports this. I would like to install Windows to an existing partition in my disk. I read that Windows will try to create an EFI partition nonetheless. How does the procedure go? here's what I am guessing:

1. I'll delete the partitions that are free currently in my GPT disk. leave that as free space
2. I'll boot from a windows ISO and point to that free space to do whatever it wants there.
3. Windows will create a couple of partitions there, for the EFI bootloader and a root partition. This all in Disk 1.
4. After that I will have to rewrite my bootloader in Disk 2 to chainload Windows on disk 1.

Is this how it would work? Is it safe to give Windows the free space on Disk 1 or will it attempt to remove also the existing partitions with actual data there?

Thanks in advance.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 24,088

Re: installing windows on a pre-existing partition

Windows does not remove anything that's already existing.  It should be safe to install that yes. What can happen is that your UEFI reorders it's bootloaders so that Windows is the primary boot but this should be trivially fixable either directly from the UEFI or via setting up the bootloader again from a normal live disk.

But this is technically a Windows question and you might want to ask that somewhere else, but I have yet to see a Windows actively change something other than the space you give it during the install.

Last edited by V1del (2021-08-05 11:57:27)

potuz

Member

Registered: 2009-10-23

Posts: 129

Re: installing windows on a pre-existing partition

Thanks for confirming this!