Hi guys, I have read many forum posts on this issue, but none have the same circumstances as mine. Late 2011 Macbook pro 13" Fresh install of Sierra, had the problem in previous installs of MacOS. New Battery (also happened on the old battery, hence the replacement) Symptom 1: The the computer has the magsafe in and I take it out, the laptop flashes up the shutdown box asking if I want to shut the Mac down, then turns off a second later without me doing anything. Symptom 2: If I shut the Mac down myself properly with the magsafe still in, let it shutdown, and then remove the magsafe the laptop turns on by itself and runs off battery fine. Previous to the shutdown/battery problem happening, I was having performance issues with the Macbook running off battery, following the advise on a different support page, the post recommended to find, locate and delete a specific .plist file: "Find the the plist file that corresponds to your Model Identifier e.g. "MacBookPro8,1.plist" Move it to the trash and delete it Restart and everything should now be fine." After I did the above, the Mac actually worked well, the performance issue was gone. About two weeks later, this battery issue presented and nothing I have tried since has worked. Here is what I have tried; I have already replaced the battery -Reinstalled Sierra from App store (not a complete fresh install) -PRAM reset -SMC reset -Apple diagnostics Any other ideas guys? I am not sure if it is related to the .plist file in a previous install of Sierra, but I am not sure how that can effect the Macbook if it is turned off. For example, if the Macbook turned off when I unplug the magsafe, I should be able to power it back up unplugged if it were an OS problem, I would assume.