Try an SMC reset. Justifications for doing that include:
The computer doesn't respond to the power button when pressed.
A portable Mac doesn't appear to respond properly when you close or open the lid.
The computer sleeps or shuts down unexpectedly.
I'm experiencing similar problems. My one week old MacBook Pro 13 inch (mid 2012) has been randomly shutting off. This has happened about 4 or 5 times now. I'm not positive, but I believe it only happens when the power cable is not connected and I am on battery power. Each time it has happened I've checked the battery level and it has been above 50%, so it's not the battery dying. There are no warning messages, nothing, the unit just shuts off. Every time it has shut off I've been in some sort of video event (streaming video, viewing video, generally when I'm in Safari).
Processor 2.5 GHz Intel Core i5
Memory 4 GB 1600 MHz DDR3
Graphics Intel HD Graphics 4000 384 MB
Software Mac OS X Lion 10.7.4 (11E2620)
I will try resetting the SMC and see what happens, then report back in a few days.
UPDATE: Bad news. Yesterday morning I did all the steps prescribed by Apple here: SMC reset -- up to and including the SMC reset. Ran my MBP on battery all day, did intensive video usage. Then connected to power and had a two hour skype video conference. No problems.
I disconnected from power and with 83% battery left I closed my MBP and let it sleep for the night. This morning when I opened the cover.... nothing. The unit had shut off during the night while in sleep mode (disconnected from the power charger). When I powered up the battery had an 82% charge.
If it's shutting off in sleep mode when nothing is running and the unit is completely cooled, it has to be a hardware or battery problem.
Are you quite certain you have not configured your Mac to automatically shut down on schedule with Energy Saver?
To potentially diagnose the reasons your computer shut down, use the following Terminal command
pmset -g log
It maintains a comprehensive log of system sleep and wake events for several days.
To determine the times your Mac was last shut down use the terminal command
I double-checked Energy Saver and there is no schedule set for automatic shutdown in either Battery mode or Power Adaptor mode.
Thanks for the terminal commands. This will help me zero in on the events occurring at the time the device shuts off. The "last" command lists 5 crashes since July 3rd. There are no corresponding entries at those times in the log from the "pmset" command. The console system log has so many entries at those times it's hard to tell looking back what may or may not be relevant. I'm going to wait until the next shut off event so the exact sequence of events is fresh in my mind, then compare the information from "last" "pmset" and the console system log and kernel log to see what pops out.
I'll report back then.
If it shut down due to a crash, a crash log may have been generated. Open Console and look for a CrashReporter log entry. That may indicate the process that caused the automatic shutdown.
When you get more information, post a brand new question with a description of the symptoms and everything you did so far. Doing so will almost certainly solicit more suggestions. The only reason I found this post was that I posted a response a long time ago (March). The original question has become stale and few people will bother to read any further.
I have also been experiencing a random shut down issue with my late 2006 (Basically 2007) Black MacBook. I bought it used and with a third-party Ebay battery. The battery is relatively new and worked fine when I first got it. However, now it shuts down at 60% and then it won't fully boot up without being connected to the AC adapter. I've tried an SMC reset to no avail and I cannot calibrate it since it will no longer fully discharge. All software is fully up to date as well. Below is my battery information. I would appreciate any help that can be given.
Serial Number: ˇˇ
Device name: ASMB013
Pack Lot Code: 0001
PCB Lot Code: 0000
Firmware Version: 0102
Hardware Revision: 0300
Cell Revision: 0100
Charge remaining (mAh): 2741
Fully charged: No
Full charge capacity (mAh): 4456
Cycle count: 49
Battery Installed: Yes
Amperage (mA): -1390
Voltage (mV): 11228
Hey Guys I'm new for the forms and have been searching this problem for a while now.
I have an older aluminum body macbook (13" I believe) and am having issues with it turning off randomally. I'm almost 100% convinced that it deals with the graphics and possibly the RAM. I read multiple other posts about people having this issue and having it resolved by simply swapping the RAM cards around and making sure they have good contact. I did this but am still having the issues. Its not a power issue cause the computer is plugged in and has full power. It appears that anytime I watch any video clip from the internet or on my hard drive it will randomally shut down. Its like the screen shuts off because when I press the power button to turn back on it "turns it off" (according to the white light that blinks; like its alive) and then I have to press the power button a second time to turn it back on.
So to sum it up i'm almost positive that it is dealing with graphics or RAM. I'm not sure of what else to try but I am sure I'm not taking it to apple care cause they always tell me to just buy a new computer. This issue isn't bad enough for me to pay them another $2000 for a computer that could end up the same way in a year or so.