pearOS NiceC0re (Arch-based)
pearOS ships GRUB with os-prober already enabled (GRUB_DISABLE_OS_PROBER=false) and os-prober/ntfs-3g already installed, so detecting Windows and adding it to the boot menu is automatic - you don't need to enable anything manually.
Before installing:
- Turn off Fast Startup in Windows power settings and fully shut down (not just restart). Fast Startup leaves the Windows partition hibernated, and Calamares' partition tool (
kpmcore) will refuse to resize or even see a hibernated NTFS partition properly - this is the #1 cause of "alongside" not showing up. - Make sure Windows is installed in UEFI mode with GPT partitioning (most PCs from the last ~10 years are), and boot the pearOS installer in UEFI mode too - mixing BIOS/UEFI between the two OSes is the most common cause of a broken dual-boot.
- You do not need to shrink the Windows partition yourself first - see below.
During install (Calamares):
- On the partitioning step, pick Install alongside - Calamares can resize your existing Windows (NTFS) partition live with a drag slider, no need to shrink it from Windows Disk Management beforehand.
- If "alongside" isn't offered (usually because Fast Startup/hibernation is still on, or Windows wasn't installed in UEFI/GPT), partition manually instead: create a root partition in free space, and reuse Windows' existing EFI System Partition (don't create a new one) so both bootloaders share it.
After install:
- GRUB (not Ploader - Ploader only boots the live USB) is installed to the shared EFI partition, and Windows should already show up as a boot entry.
- If Windows is missing from the menu, re-scan and regenerate manually:
sudo os-prober
sudo grub-mkconfig -o /boot/grub/grub.cfg
- If your PC still boots straight into Windows, change the boot order in your motherboard's UEFI settings so GRUB boots first.
This also works for dual-booting with another Linux distro - os-prober picks those up the same way.