Inherited MBA from a friend. It had been upgraded to Sierra from Lion. Ran fine for 2 months then 2 wks ago got the gray screen with flashing folder/question mark at startup. Per advice from Apple Community got into internet recovery mode. Apple logo, startup disk...nothing...got into Disk utility to repair disk but there wasno Mackintosh HD it only showed Disk0 (unmounted) with a yellow folde under it Apple Base X System. When I clicked on either one they did not open in the First Aid or any of the adjoining tabs. the pnly option available was to get info. Got into Terminal and the diskutil list report did not show the Mac HD Disk . Couldnt reinstall Lion either. The only thing that works is Safari (ooooold version) on a limited basis. Is there any hope of restoring recovery HD start up disk?.
