new battery won't chargeMacBook Pro 15" Core Duo Model A1286 My original battery was swollen, so I bought a replacement. It worked fine for 3 months....
Answer to: Is there a way to test for sluggishness?I just had the same issue on my late 2011 15" yosemite. It was extremely sluggish - felt like I was screen sharing. Repaired permissions, checked RAM usage, all was in order. I switched users and the problem disappeared! My tech told me there's a way to fix a user without deleting it, but I didn't bother. I just deleted the bad user account, as I had nothing I needed to salvage.