I have a 13" MacBook which is working normally except for this new issue. In the past when the battery drains to near zero, everything is saved so when the power is restored, you see a gray version of your screen as it's restoring everything to the point where the battery went dead. I'm not sure if it's called hibernate, deep sleep, or neither. The problem now is that when the battery drains to zero, the computer just shuts down as expected. However, upon restart, it's not restoring to last state. It just boots up normally. What's causing it to boot instead of restoring to last state? Thanks.