Fans Start Running While in Sleep Mode

I have tried to reset the SMC, but I cannot tell if I was successful. Note that Apple's web site says I should unplug the power before holding down the Shift-Control-Option and then Power keys, while every other site like OS X Daily and many others recommend keeping the Mac plugged in while performing the procedure, and looking for the light on the MagSafe to blink or change color (maybe).

I've performed both, several times over, but I cannot tell if I successfully reset the SMC. If it's supposed to reset the power (Energy Saver) settings in the Control Panel, like the time it takes to dim/shut-off the display, well, nothing changed so I would have to assume the SMC was not reset.

I will let the MBP sit and sleep and see if the fans start doing their thing again, but I'm wondering if it is worth my taking it to an Apple Store and having them look at it. It's bad enough that the fans go crazy while in sleep mode, worse that it sometimes leads to a panic that may result it my losing work, but now I can't even tell if I'm doing anything to fix it.

Otherwise, this MBP has been fantastic for the month or two I've owned it, pushing it hard to drive two external monitors and Parallels (and yes, the problem can occur regardless of whether I am pushing it or just letting it sit idle with no Parallels or external monitors operating). So, I really, really want to get this problem resolved.

It did it again. This time, while on power, lid open, and with a USB mouse plugged in, wireless activated but BlueTooth disabled. MBP (refurbished 2015 model, 15-inch) went into screensaver, and then went to sleep. Then fans started running on full. All of this within an hour.

What's different was that this time the MBP was unresponsive, would not wake up, even if I unplugged and re-plugged the power and the USB mouse. MBP shut down when I held down the power switch for a while. Pressed the power switch to re-start. No response. Pressed again. Text message appeared that the MBP was re-starting AFTER A PANIC. The GUI then appeared, with the message that the machine had not shut down properly.

I am now going to try the suggestion above re: resetting the SMC, and see what happens.

It's gotten worse. I had put the MBP to sleep, put it in my bag. Hours later, I pulled it out of the bag and noted it was warm. Put it to my ear, I can hear the fans are running quietly... what kind of "sleep" is this? Open the MBP, the desktop appears, but frozen: clock in the menu bar stuck on the time when I put it to sleep, no mouse pointer at first but then it appears, and it responds to the trackpad to move across the screen, but it's stuck as a particular kind of pointer, unresponsive to the application underneath. Clicks are ignored. Clock is still frozen. If I let the MBP sit a while to "snap out of it", then the screen will dim to black after a while, but nothing else. A keypress will bring the screen back to where it was, frozen except for a dumb mouse pointer moving with the trackpad. A press on the power key is unresponsive. Only a long-press on the power key to force shutdown causes the machine to shutdown. The Mac then restarts fine.

But there is DEFINITELY something wrong with this MBP and sleeping, and I've tried everything I know.

I have called Apple Support, and was pleased that they replied with telephone-based support (with live people) several times, and each time they were attentive, polite and knowledgeable.

The problem is not solved yet, but they directed me to do some troubleshooting to try and better figure out what's going on.

First, they asked me to boot in "Safe Mode", which is to hold down the shift key when the machine boots up. This resulted in the MBP working fine! Mind you, I'm stuck with my only test being setting the screensaver to 5 minutes and the Energy Saver (plugged in) setting to shut off the screen at 10 minutes, and then waiting to see what happens. Logged in as myself, but in "Safe Mode", I woke the MBP from sleep many times and experienced no problems.

Next, they asked me to create a new user account with admin privileges, log in with that, and see what happens. This isn't "Safe Mode", but the new account would have any of the 3d-party software loading as in my "normal" account. Indeed, the menu bar in the new account is just about empty, save some standard Apple stuff like WiFi and the clock.

The MBP crashed while asleep. Tapping on a key wakes up the screen, but it's frozen on the screensaver image. The Caps-Lock key will turn its light on and off if I tap it, but otherwise the MBP is completely unresponsive. Curiously, if I let it alone, the screen will go black after a time, and I can again tap on a key and the screen will brighten again, but the result is the same: frozen screensaver image (the screensaver I am using is the standard, stock screensaver that shows some text, the Apple logo, and the time of day). The fans aren't running like crazy, nor is the machine hot, but the MBP is basically comatose and I have no choice but to force power-down and restart.

Upon restart, I get the message "You shut down your computer because of a problem", but no other information.

BTW, I'm doing all this "by the book" because I bought this Mac refurbished from Apple, so it's under warranty. I'm expecting to take it in for service, but I'm doing all I can to so they do the right thing, which seems to me more and more likely to be a motherboard-swap rather than wiping my drive and re-installing the OS.

As a further experiment, I noticed that the login screen, which I usually skip and just log in automatically, has a button on it for going to sleep. Tried it. Waited. Tapped the keyboard, MBP came back up fine.

Now this is interesting. Start up the mac, arrive at the login screen, press the sleep button, let it sit for a while. Press a key to wake the mac, COMATOSE! Login screen appears, mouse pointer moves, but NON-RESPONSIVE! Clock in upper-right corner stuck at whenever the machine died (as best I can tell). I never even got a desktop running, and still the mac dies in its sleep!

Tried the built-in Apple diagnostics (press "D" while restarting).

Result?

"No issues found" (reference code ADP000). 😝