Resetting a MacBook Air (2017)

It seems like you may have accidentally messed up the partitioning on your Macbook Air, resulting in the flashing question mark when you try to boot it. This typically indicates that the Mac cannot find a valid startup disk.

To resolve this issue, you can try the following steps:

1. Shut down your Macbook Air completely.

2. Connect your Macbook Air to your Wi-Fi network so that it can access the internet.

3. Turn on your Macbook Air and immediately press and hold the Command + Option + R keys until you see the spinning globe or Apple logo.

  - This will start your Mac in Internet Recovery mode, which allows you to reinstall macOS.

4. Wait for the "macOS Utilities" window to appear.

5. Select "Reinstall macOS" or "Reinstall OS X" from the options and click "Continue."

6. Follow the on-screen instructions to reinstall macOS on your Macbook Air.

  - This process may take some time, so be patient.

7. Once the reinstallation is complete, you should have a fresh copy of macOS on your Macbook Air.

8. At this point, you can choose to set up your Macbook Air as a new device or restore from a Time Machine backup.

After performing these steps, your Macbook Air should no longer show the flashing question mark and will be reset to factory settings.

If you continue to experience issues or the problem persists, it may be helpful to visit an Apple Store or contact Apple Support for further assistance.

Here are the instructions to follow:

What to do before you sell, give away, trade in, or recycle your Mac - Apple Support