Looking for some info / explanation ... rMB running the latest (10.12.4). It developed a stutter when using the built in trackpad. Everything looked good, was charged... It was looking good except for the stutter. Tried restarting, rebooting ... no joy. Found the stutter stopped when I unplugged it from the charger. I let it run down to 20%, plugged back in and allowed to recharge for a bit and the stutter was back. Went searching (Google it ). What I found was that although the stock charger properly charged my rMB, when I changed out the charger and plugged the cable into a USB charging tower, the stutter went away. Plugged back into the stock charger, stutter was back. btw - found this potential cause in my Google search. Can someone explain to me how the charger can cause this? The stutter comes into play no matter the battery percent only as long as I am plugged into the stock charger. Thanks!