Flashing folder with question mark
This happened to me today; Turned on the 2013 MBA and got the Grey screen and then the Folder with a Question Mark slowly flashing. I've search all over the net, tried a clean install but the MBA is not seeing the hard drive. Scheduled an appt. at the Apple Store. To wit a few points I have to pass along.
1) Make sure you have a copy of your serial number written down. Its very hard to read the tiny serial number on the back of the MBA. Why because small scratches don't help you read the tiny writing. Which brings me to point two.
2) A shell cover will save you from minor scratches i.e. on or near the serial number
3) I would be a good idea to have a recovery compact flash or CD rom. Its kinda tough when everything is down. Even though this didn't work for me due to a faulty hard drive. It would have saved me if I only had corruption.