Chosen Solution
Errotic and Jumpy trackpad Somehow my trackpad become jumpy.I’ve tried to clean the trackpad and my hand. But it stilll happen. it only happen when my Mac is connected to the internet. but not always when my my Mac is connected it happen (got it?). I’ve asked the apple store, but they dind’t know why either.
Make sure that the trackpad is dry since this symptom of jumpy cursor. A moist trackpad causes the capacitance that the trackpad use to know where your finger is to see the moisture as a “false finger” thus the the jumpy cursor.
Take out the battery, flip the machine over and check the ribbon cable that runs from the trackpad to the keyboard, to the connector. Known issues are: loose at connection point, or ribbon could be wrinkled, lose, crimped so that pressing keys moves the connector. Some people have had luck just pressing it flat against the keyboard,(especially where it passes through the slot in the sidewall) other have shimmed the cable using a folded sticky note beween the cable and the battery. Good Luck, N.
I have had this problem for a while this winter (it’s March now). Tried different pad settings, cleaning the pad, etc. No help. I noticed one day that it worked OK for about 15 minutes after I had washed dishes, then went bonkers again. Then we had a warm day with a lot of rain and it worked OK. I decided static electricity had something to do with it. I tried a cell phone stylus instead of my finger. Worked OK. Since I sometimes get a static shock when I touch the laptop case I tried keeping my other hand in contact with the case, worked OK. Still looking for a really good solution, but I’m close. Being grounded while trackpadding will probably do the trick. Also, one of those bedside humidifiers would likely be a solution.
