Macs are not always perfect. There are still many problems happening with it and the macOS can get crashed and fail to start up. Here are solutions you should do if your MacBook Air won’t boot up.
Assume that your MacBook Air is not responding when pressing the Power button. In case your Mac responds but it fails to start up, you should enter Recovery Mode.
Connect Your MacBook Air to Adapter
Make sure your MacBook Air is connected to a power source. Try to unplug the power cable and then connect it to another outlet. There is a small chance that your charger gets damaged with your knowledge. If the battery of your MacBook Air is completely dead and exhausted, you need to wait a few minutes after connecting it to the power. After that, try to power it on. Your Mac cannot start up immediately right after you connect it with the power source.
Make a Power-Cycle on your Mac
If your MacBook Air is not responding after pressing the Power key, there is a solution that is preventing the power to it and forcing it to restart.
On modern MacBook Air models that do not allow removing the battery, press the Power key and hold it for 10 seconds. If your computer works again, it will then cut the power to your Mac and force your device to restart.
If you Mac can remove the battery, just unplug it, remove your Mac battery, wait for a minute and insert it again.
Reset System Management Controller (SMC)
In a few cases, resetting System Management Controller (SMC) on your MacBook Air is a helpful solution. It’s one of the last solutions you should try if your MacBook Air does not respond after you press the Power button.
For MacBook without a removable battery, you should connect it to the charger. After that, press and hold Shift+Control+Option buttons on the keyboard and then Power button. Release four buttons at the same time after a few seconds and hit the Power button to turn on your Mac.
If your Mac allows removing the battery, just remove the battery from your Mac. Hold down the Power button and keep it for a few seconds. Release it, then reinsert the battery into your Mac, and press the Power button to switch it back on.
Enter Disk Utility in Recovery Mode
Assuming that your Mac cannot boot up but is impossible to load macOS properly, it’s absolutely a software problem. The high chance the drive of your Mac might get corrupted, you can solve it from the recovery mode
To boot your Mac into recovery mode, just press firmly the Command + R keys during the startup process. You have to press them immediately after you hear a chime sound. Wait for a few seconds and your Mac will boot into the recovery mode. Otherwise, you pressed the keys too late. Restart your MacBook Air and try it again.
Once your computer enters recovery mode, click on the “Disk Utility” option, choose the First Aid tab to start repairing your Mac drive. The Disk Utility tool will perform a file system check and you no need to run it manually.
Restore Your Mac from Recovery Mode
If the Disk Utility method did not help you, you should reinstall macOS on your MacBook Air.
You can take advantage of the “Reinstall OS X” option in the recovery mode to get the latest version of macOS and then re-install on your Mac. You can also perform a restoration from a Time Machine backup you created previously. In case the operating system of your Mac gets damaged, it will replace it with a clean copy of the newest macOS version.
If your Mac is impossible to startup no matter how many times you hit the Power button, or if the recovery did not work, then your MacBook Air is suffering a hardware problem.
If your MacBook is still under warranty, you can contact or bring it to an Apple Store for further assistance. Even if it’s out of warranty, you should still take it Apple Store for a reparation.