Chosen Solution
Hi! I purchased my Mac from a fellow friend who needed money. And he gave it to me with a broken trackpad on the top left edge. Coming back to today, I purchased the replacement trackpad and I could and did replace the factory one. Thing is that when installed I proceed to test it, and it’s somewhat like laggy from the half to the top of the trackpad itself. (Don’t know if I explained myself properly). Plus I couldn’t do a drag and drop action using two fingers. What could it be? Installed back the factory one and it works like a charm. Is it the trackpad thats not fully original or is it defective? Thanks.
Try going under the Apple in the upper left hand corner to System Preferences > Trackpad and reset the speed and see how it is currently set up.
Try to swap the ribbon cable from your old trackpad to the the new one. If you have the same problem then the new trackpad is faulty. Ask for a replacement.
