MBP Running slow when its on batteries .. working fine when plugged to the charger ?!

It worked just fine with Sierra. Now I just updated to High Sierra and the problem came back. I repeated the process and it worked again like a charm! Thank you!

Just noticed the file in my case is MacBookPro8_1.plist and its path is slightly different:

/System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC _PlatformPlugin.kext/Contents

MacBookPro8_1.plist to trash!

I just tried this on a mid-2010 Macbook Pro on a fresh installation of macOS Sierra. The computer had a history of water damage but there was no damage visibly obvious on the board. It had been examined by Apple several years previously when water damage had occurred. The computer had sat for a year or two without use and had such a badly bloated battery that the touchpad was popping out of the front about an inch (hard to believe the touchpad could withstand this..). After installing a new battery, doing a fresh install of Sierra, doing a hard reset with the battery out and repeatedly resetting the SMC the computer continued to exhibit signs of SMC issues -- the keyboard backlight was vacillating between on and disabled and the computer was running so slowly when it was off the charger that it was nonfunctional. The computer failed Apple Hardware Test for sensor failure: 4SNS/1/40000001:VP0R-0.000.

I am guessing that this sensor is in some way related to the battery and how the SMC detects it and adjusts the computer's power settings accordingly. Removing this KEXT resolved all the visible SMC issues like the vacillating keyboard backlight and the slowness off the charger. The changes were persistent across shutdowns and after running the Sierra 10.12.6 update the changes remained. With the KEXT removed I haven't noticed any differences between fan operation or CPU temp in stress testing and the computer is correctly recognizing that it's running on battery when it's off the charger.

Although this fix works for the visible symptoms, Apple power components are intricate and altering SMC settings have pretty serious implications, including overusing and overheating your motherboard from a lack of proper settings. Although I implemented this I'm continuing to monitor the computer. This problem indicates a motherboard sensor or component failure. Ultimately, if you're having this issue running Apple Hardware Test or Apple Diagnostics wouldn't be a bad idea.

Apple Diagnostics is the newer version of AHT and is available on computers released June 2013 and after. You can hold down D at startup (after the screen comes on) to access either of these tools. More information on these diagnostics:

How to use Apple Diagnostics on your Mac - Apple Support

How to use Apple Hardware Test on your Mac - Apple Support

For some older computers, an external CD is required. If you don't have this CD, you can find the version of AHT that fits your model computer (7,1, 8,1, etc.) online. If anyone has similar experiences and runs the diagnostics, it would be interesting to hear the results.

How are you able to move the file to trash? I get a message saying I’m unable to delete because it is part of macOS. :-/

it worked!! in yosemite too! thank you!!

you will find it here /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SM C_PlatformPlugin.kext/Contents/Resources

I reached to the file mentioned, however unable to delete nor move to thrash. There is a pop up message "MacBookPro8_1.plist can't be modified or deleted because it's required by macOS". Appreciate further help....

Did you disable "System Integrity Protection (SIP)" yet?

I did just only three steps

- Disable SIP with "terminal" under "recovery system" mode

- Find MacBookpro8_1.plist and delete

- Enable SIP

Here is how to disable and enable SIP

https://www.igeeksblog.com/how-to-disable-system-integrity-protection-on-mac/

Hope it works with you too

^^

Thanks everybody to all replies. It helps a lot to future people like me. I still have a question. After deleting the plist file, is it ok to the system works without it ? After restarting the mac i checked if the system could created the file, but it wasn't there. It seems my mac is running ok even without it.

Thanks a lot man. It really worked. I tried many option to fix this. First i thought battery is faulty then i swapped with another one from my friends macbook pro . But no solution. But this one worked for me. Though i had to disable system integrity check from recovery mode to delete that file. But it really worked , big thanks for sharing this knowledge.

RoXy1988 wrote:

P.s : I cleaned it up

How did you do that?

First, if you have encrypted any files using MacKeeper, unencrypt them using MacKeeper.

Then, read and follow the instructions here: http://mackeeper.zeobit.com/uninstall_mackeeper

You do not need to answer the "reason for uninstalling" question that appears.

Macs do not need "cleaning". Never install MacKeeper or anything like it ever again.

Reset the SMC, then test your MacBook Pro again.

SMC reset:

Before Resetting the SMC

Try each of the following steps in this order before you reset the SMC. Test the issue after completing each troubleshooting step to determine if the issue still occurs.

1. Press Command + Option + Escape to force quit any application that is not responding.
2. Put your Mac to sleep by choosing the Apple () menu from the upper-left menu bar and then choosing Sleep. Wake the computer after it has gone to sleep.
3. Restart your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Restart.
4. Shut down your Mac by choosing the Apple () menu from the upper-left menu bar and then choosing Shut Down.

Resetting the SMC on portables with a battery you should not remove on your own

1. Shut down the computer.
2. Plug in the MagSafe power adapter to a power source, connecting it to the Mac if its not already connected.
3. On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
4. Release all the keys and the power button at the same time.
5. Press the power button to turn on the computer.