Need help
Got a new MacBook Air so tried to reset the old one to sell, when doing so now upon boot it flashes a ? With support.apple.com/nac/startup
Question marked as
You apparently did not follow instructions and have erased the HD. Therefore when the Mac is looking for an OS, none is found. Please read the link below for details.
What to do before you sell, give away, or trade in your Mac - Apple Support