Hello guys!
I have (had?) the same problem than you.
• Apple MacBook Pro (3.1) (15") (2007)
(CPU = Intel Core 2 Duo 2.4 GHz)
(SD-RAM = DDR2 667 MHz, 4 Go)
(Graph Card = nVidia GeForce 8600M GT, 256 Mo)
• For several years,
my MacBook Pro was running quite happily with Mac OS 10.6 (Snow Leopard).
When I was abusing on resource-hungry apps launched together,
it simply ran slower and with more fan noises, but NEVER AUTO-SHUTDOWN.
• After I upgraded (not sure about this one...) to Mac OS 10.8 (Mountain Lion),
I started to experience unexpected sudden AUTO-SHUTDOWNS,
but only on a weekly basis (albeit using my computer everyday).
During last summer 2016, I noticed that
the EXTERNAL/AMBIENT TEMPERATURE makes the problem worse.
I use my laptop computer for musical purposes,
so, in the middle of the month of August, I bring it on stage for a live concert.
While not exposed directly to the sun
the poor MacBook Pro had to suffer a full-length afternoon of hot weather.
I tried to make the experience easier for it
by installing 2 fans (a big one and a tiny one) just in front of it.
Nonetheless, in the middle of the show (and in the middle of a song!),
I experienced a sudden shutdown, and had to restart the whole thing.
Hopefully, the guitarist my dude saved the day by improvising an interlude!
• Afterwards,
I upgraded (neither sure about this one...) to Mac OS 10.11.6 (15G31) (El Capitan).
I was very disappointed about the new Graphical User Interface look (which is just plain ugly, I feel),
so I heavily customized it
(with XRevert + XtraFinder + Total Finder + cDock + OnyX + MenuMeters + you name it...)
But then, those sudden shutdowns began to happen more frequently (say, once a day.)
Very very disappointing and annoying!
In my quest to identify the apps that could be the cause of the problem,
I noticed several things:
(1)
Just before the (dreaded) black screen,
I have just a second of time (or so) to read the CPU Meters.
Verdict: contrary to what I supposed,
the shutdowns are not directly related to a high CPU usage
They may be indirectly related, however.
(2)
The shutdown often happens when
I'm listening to some audio files located on an external drive, using VLC or iTunes.
But it also happens when I use other apps, however.
(3)
Someone here talked about the System Preferences.
I also tried to tweak these settings.
In particular, I tried to set the Drive Shutdown Time to "never".
But this didn't prevent the unexpected sudden System Shutdowns.
(4)
Similarly,
deactivating the OS Configurators/Customizators
(XRevert + XtraFinder + Total Finder + cDock + OnyX + MenuMeters + you name it...)
doesn't cure the problem, so it's not their fault.
(5)
I wondered if this could had something to do with the InterNet.
Nope: when connected to the web or not, the same problem is still happening.
• This evening, the following happened :
I was running (Ableton) Live (a music app which is both CPU-hungry and RAM-hungry),
while at the same time I was looking for something on Internet, using (Google) Chrome.
As too often, a page for an On-Line Video Game automatically opened.
Normally, I immediately close that kind of unwanted tabs.
But this time, the game looked nice (for those who care, it's called Elvenar),
so I decided to try it a few minutes.
And then... Bam! Shutdown!
As usual, I was upset, but this event gave me the idea to test something.
As a first step to find the cause, I tried to REPRODUCE THE PROBLEM AT WILL.
I restarted the computer, and choose the option to
re-open all the apps that were opened before the auto-shutdown.
With exactly those same apps and web pages,
I experienced several auto-shutdowns in a row.
OK, these two kinds of apps (Music & Video Games) are both CPU-hungry & RAM-hungry,
but I'm pretty sure I would have been able to
do the same with Snow Leopard without any System Auto-Shutdown.
• Finally, I decided to really search for the CAUSE (and hopefully, a SOLUTION) to this problem.
That's how I ended on this forum.
Reading what you said you tried gave me an idea.
Since those AUTO-SHUTDOWNS
have something to do with the TEMPERATURE,
and since it is well known that Batteries produce HEAT,
I was wondering if the cause could be the BATTERY.
So I REMOVED THE BATTERY, went on AC Power alone,
LAUNCHED THE SAME APPS as before...
and EVERYTHING RUNS PERFECTLY !
I must admit that
the Battery of my MacBook Pro is almost (or definitively...) dead
(I plan to buy a new one very soon),
so I'm very curious to know what will happen if you remove YOURS.
Oh no, please! Don't tell me all of you run your laptop computer on a DEAD BATTERY... :v)
~ KENDALPH — (2017-01-17 Tuesday 04:42 GMT+1) ~