My MacBook Air shuts down unexpectedly and it doesn't turn on until multiple tries. Any help?

I had the same issue with my MBA Early 2014 model. The laptop used to shutdown at once unexpectedly.

In my case if I used the laptop while connecting the adapter, the laptop won't turn off. So, i thought the problem was with the battery connection. I opened the back panel of the laptop and reinserted the battery connection wire and the problem is no more with me.

If you want to try this you can just refer to 'IFIXIT' for disassembling and assembling videos.

Did you erase the drive before reinstalling OS X? Also, see Troubleshooting a MacBook Air that won't turn on.

Clean Install of Sierra or El Capitan on a Clean Disk

1. Restart the computer. Immediately after the chime hold down the Command-Option-Rkeys until a globe appears.
2. The Utility Menu will appear in from 5-20 minutes. Be patient.
3. Select Disk Utility and click on the Continue button.
4. When Disk Utility loads select the drive (usually, the out-dented entry) from the side list.
5. Click on the Erase tab in Disk Utility's main window. A panel will drop down.
6. Set the partition scheme to GUID.
7. Set the Format type to Mac OS Extended (Journaled.)
8. Click on the Apply button, then click on the Done button when it activates.
9. Quit Disk Utility and return to the Utility Menu.
10. Select Reinstall OS X and click on the Continue button.

This should install the version of OS X that was pre-installed when the computer was new.

Hi,

Try the troubleshooting help in this support article > If your Mac won't turn on - Apple Support