The symptoms suggest a possible battery fault.
Your MacBook Air shuts down unexpectedly at 30–40% charge, then shows around 10% after restarting and rapidly returns to its previous percentage.
This may indicate that the battery can no longer deliver power reliably or that its charge-level readings are inaccurate.
The age of the MacBook is relevant. The M2 MacBook Air was released in 2022, so the earliest models are now around four years old.
Lithium-ion batteries naturally deteriorate with age and charging cycles. Apple rates the battery for up to 1,000 charge cycles, but problems can occur earlier.
First, check System Settings >> Battery >> Battery Health.
If the status says “Service Recommended,” the battery may need replacing.
See Apple's battery health guidance.
You can also check the cycle count under Apple menu >> System Information >> Power, following Apple's instructions.
Next, run Apple Diagnostics.
Shut down your Mac, then press and hold the power button until startup options appear. Release the button and press and hold Command (⌘) + D until diagnostics starts. Follow the on-screen instructions and record any reference codes.
When to contact Apple:
If Battery Health shows “Service Recommended” or diagnostics returns a battery or power-related reference code, contact Apple or an Apple Authorized Service Provider to arrange an assessment.
Have the computer evaluated by the Professionals who have the Special Hardware Software and Expertise to diagnose the issue and offer possible solutions
Make an Appointment at the Apple Genius Bar or call 1 800 MyApple and have them evaluate the computer
Other location Call Centres
Contact Apple for support and service
If both checks appear normal but the MacBook continues shutting down at 30–40%, contact Apple anyway rather than waiting for the problem to worsen. Intermittent battery faults may not be detected by diagnostics. Explain the shutdowns and sudden percentage changes, and ask for the battery and power-delivery system to be tested.
If the problem stops after updating macOS, monitor the MacBook. If it recurs, arrange an assessment. Back up important files and avoid relying on the displayed battery percentage until the issue is resolved.
Given the MacBook's age and these symptoms, battery deterioration is a strong possibility, although testing is needed to confirm the cause.
User level: Level 1 (4 points)
