Mind letting us know why or how? When I installed it almost a year ago on my desktop, I did install it as a dual boot option with no issues. Of course this doesn’t mean there aren’t issues I just didn’t run into. I’m also not new to Linux and didn’t pick a fully default install, if that makes a difference. So I could’ve probably fixed it if it did break, but it never gave me any issues.

Well in my case, using systemd-boot:

• Window's default EFI partition was too small to hold the kernel, but CachyOS setup didn't check for this and just failed to boot linux. You wouldn't run into this issue on a second disk I suppose, but I did on a single NVMe shared with Windows.

• Sometimes, if you do share an EFI partition between Windows/Linux, Windows Update will randomly nuke it and break your linux install.

• I also had an instance where systemd-boot just stopped detecting Windows after awhile, and it needed some manual fixing.

Basically, trying to install linux on the default EFI partition next to Windows is a risky default, and Windows users new to linux aren't going to know anything about how to fix it.

The fix is to just make a second EFI partition on the drive, but the installer doesn't do this by default. And I encountered this a long time ago, but noticed the issue was still present when testing Cachy on another PC, by chance.