Why Did My MacBook Shut Down on Its Own?

• MotherBoard / LogicBoard Hardware Issue
• Overheating
• Mac OS Error 
• Virus / Malware

Fix and Solution for Macbook Auto Shutdown
There could be a number of reasons why your MacBook is shutting down automatically. Try these suggestions for solutions:

1. Look for upgrades in the software: Verify that the most recent version of macOS is installed on your MacBook. Click Software Update after choosing System Preferences from the Apple menu. Install and download any available updates.

2. Monitor for overheating: Your MacBook may shut down on its own if it becomes too hot. To determine whether your MacBook is overheating, feel the top and bottom surfaces for warmth or hear the fans running. Try using your MacBook on a flat surface if you think it might be overheated, or acquire a cooling pad to help with heat dissipation.

3. System Management Controller (SMC) reset: On your MacBook, the SMC is the system that manages heat control, power management, and other system-level operations. An auto-shutdown MacBook may occasionally be resolved with an SMC reset. The SMC can be reset as follows:

• Shut down your MacBook.
• Press and hold the Shift + Control + Option keys on the left side of the keyboard and then press the power button at the same time.
• Release all the keys and the power button at the same time.
• Press the power button again to turn on your MacBook.

4. Launch Apple Diagnostics: Your MacBook comes with an integrated utility called Apple Diagnostics that can assist in diagnosing hardware problems. To launch Apple Diagnostics, take the following actions:

• Shut down your MacBook.
• Press the power button and then immediately press and hold the D key.
• Keep holding the D key until Apple Diagnostics starts.
• Follow the on-screen instructions to diagnose your MacBook.

If none of the aforementioned fixes resolve the issue, you might need to bring your MacBook to the IRepair Service Center or get in touch with Apple Support for more help.