macbook air factory reset
i erased macintosh hd and restarted it but when i turn it on its just a black screen and puts a flashing image of a file with a question mark
Question marked as
The second part of the instructions 'if your mac starts up to a question mark'
tells the next steps including erase the drive and reinstall macOS. ~ If you've
not gone through first part, try that before the second.. the fix is in 2nd one.
• If your Mac starts up to a question mark - Apple Support
https://support.apple.com/en-us/HT204323
Also could be the main storage drive may be defective & need replaced.
There's also instructions what to do before sell, give away, or trading in Mac
~ the part after #7 tells what would leave Mac as new, and not personalized.
https://support.apple.com/en-us/HT201065
'Internet recovery' may help with 'disk utility' among other steps to try.
[If you tried linked Support article in upper part of this page, try it again.]
• Erase and reformat a storage device in Disk Utility on Mac - Apple Support
https://support.apple.com/guide/disk-utility/erase-and-reformat-a-storage-device-dskutl14079/mac
• How to reinstall macOS - Apple Support
https://support.apple.com/en-us/HT204904
These surmise a general path involved. Each partition may need erasure.