This needs a backstory. So, I had an old MacBook Air Model A1370, with a Snow Leopard Mac OS X 10.8.6 and updated it to a El Capitan. It had a kernel panic and I solved it by going to recovery mode by pressing the power button and then pressing alt/option button after chime. (This could be done very easily by pressing Command+R, but I did not know it). After all that, I erased my disk (Macintosh HD) by the disk utility and then tried to start up, but when I pressed the apple logo on the upper left corner and then pressed “Choose Startup Disk…” it popped up a window where i could choose a startup disk, and… no sign of any startup disk (they did not appear). At first I did not think that I had to start up my computer, but after research I knew that I had to… So, here am I. Looking at the blank white rectangle with no disks.
Now, I know what you might answer, you might say to reinstall my OS, but this cannot happen, when I logged on the recovery mode, it appeared to already have installed the update and is currently using it. I can say that, because I saw plenty of changes in looks.