Mac runs as long as plugged in, but unpredictably shuts off otherwise - clock resets I have a MacBook Pro, as shown in the image below.  Also, as I think it might use a lot of power, I run Ubuntu on a vagrant machine to test website apps.

Recently (last 2-3 months), the battery would go down to about 10%, and the Mac would just shut down. Go black.  Total restart.  AND, the clock was reset to 6:00AM.  I would reset the clock and go on with life.

Then, I started noticing this would happen at say 23% power, or 45%.  Now, it's unpredictable when it will happen.  It's never happened when I'm plugged in.

How do I solve this problem?
Pretty sure it needs a new battery.

Get coconutBattery (freeware) &amp; test.