Macbook Air: shutdown on 50% battery Target machine: MacBook Air, 13-inch, early 2014, MacOS Sierra 10.12.6, used for 4 years very carefully without any problems. 

Battery has only 70 cycles, condition reported as "Normal", and still works good on long flights. 

However, yesterday I faced a problem, when the battery was about 50%, system just performed hard shutdown. I tried to turn it on twice, it kept shutting down after 2-3 seconds after the system boot. After plugging in power it works without any problems.

I doubt if I can reproduce the problem, it means I should work from the battery in the moment of shutdown (and lose work results)

Does anyone met the problem? How to detect the reason, is it hardware or software, or just system settings (I believe, it should be warning and regular shut down, never drained the battery before)?
Judging from the symptoms I highly suspect it's an issue with the battery. I recently had my late 2013 Macbook Retina serviced because it experienced exactly the same issue: Immediate shutdown when the battery was drained to 60%. It would instantly turn back on if connected to power. My battery was 5 years old and had about 240 cycles. The apple engineer told me that the battery needs to be replaced because it was so old and coulndn't hold a charge.

What does the System Information (Click on Apple Logo while holding down option to access it) report about your battery?


Can you check what coconut battery reports about the remaining actual charge? It would be really interesting to see what the actual fully charged capacity of your battery is and the designed capacity. If it's less than 80% of the designed capacity when the battery is fully charged then I would recommend replacing the battery regardless of its cycle count.