– You can’t change C: or the EFI system partition. That’s by design. ✅ Reasonable.
If the drive has a blue bar at the top but the option is still greyed out, you might be dealing with a protected partition. This often happens with SD cards or drives pulled from other devices. The Disk Management GUI cannot delete these, but the Command Prompt can. change drive letter greyed out
It’s a frustratingly common Windows issue. You can see the drive, you know it’s there, but Windows simply refuses to let you manage it. – You can’t change C: or the EFI system partition