Q: Magic Trackpad Erratic Movement

A few of points:

1) The problem seems to vary with battery strength. This is why I have seen a pattern of thinking the problem is solved, only to have it get worse over time. Keep your batteries fresh.

2) I had a Genius Bar appointment about this Saturday. So far, the issue is not "on the radar screen" in that Apple has not issued any alerts to the Genius Baristas. However, my genius was aware of this thread.

3) He suggested going into Airport Utility and changing the radio mode setting for the Time Capsule to 5Mz. I haven't tried this yet since the fresh batteries are working.

I have a different problem when using the MTP. it works fine in normal use, I have never experienced the pointer being erratic.
However; when I switch between user profiles the MTP does not respond at all for 45 seconds after the profile switch, added to this I suffer the same symptoms with my magic mouse too.
I have a BT Keyboard that responds straight away after switching profiles.

its annoying!

I turn Time Machine off when I'm using the trackpad, and I have no problems. I'm going with cloud backup instead, though I'll probably turn Time Machine on at night.

Having the same erratic jumpy behavior. Sometimes shutting it off will fix it for a while. It is really getting annoying when you are trying to get stuff done. Went back to Magic Mouse, wish they'd fix this.

I have same problem as tonyward. My MTP freezes after changing user profiles but magic mouse still works. After a while the MTP wakes up for several changes of the user profiles but eventually it freezes permanently. I then find that the top RH corner (set to start screen saver) doesn't respond to the magic mouse so I bring up Display & Screen Saver window which then freezes with rotating coloured wheel.
Then Apple Menu items: Restart, Logout, Force Quit & About This Mac do not respond! Option Command Escape doesn't work either although Force Quit on System Preferences in the Dock does. I have to shut down on the Power Button. Then it is all Ok for a couple of days before it happens again. I have reset SMC & PRAM as suggested by Apple Care without any benefit. My SystemLog keeps reporting "cannot find com.apple.ReportCrash.self" and Automatic report in Console Preferences is greyed out. Any connection?

Just bought my MTP yesterday and I started seeing this within ~6 hours--here are my observations:

1. Airport Extreme is 802.11n/gigabit
2. I'm using ethernet and airport is disabled on both macs (though I do have a wireless network)
3. Magic mouse and wireless keyboard are not having any issues, only MTP (all are within 2 feet of each other)
4. I'm detecting 6-8 other wireless networks
5. Lastly and strangely, when my cursor starts jumping, I'm able to temporarily restore control by simply clicking the trackpad.

same here. erratic today for no apparent reason. Changed batteries but didn't help. click calms it down temporarily. Mouse is fine, just the track pad. It seems to be something in the bluetooth connection. Totally unusable this way.

Actually, mine seemed to be caused by a flash drive plugged in. As soon as removed it went back to normal. Wierd . .

I have experienced this problem with my MTP on 3 occasions. In each occurrence, the corrective action was to replace the batteries in the device. The last occurrence was tonight. Even though the battery level through System Prefs indicated 58% for the MTP, the device would not respond or would go off in a "fit" around the desktop.

As with each previous event, once I replaced the batteries, the problem disappeared. This would indicate that the power level in the MTP dipped below a threshold at which BT communication becomes erratic.

I am also suspect of the battery level reported via System Prefs. Tonight's problem was encountered at a reported 58% battery level. The previous event reported a battery level of 9%. The one prior to that was 13%.

I have found the problem:

It has something to do with interference with other hardware in the house or around the computer.

If i move the trackpad around abit on my table then the problem goes away. I have to find a 'sweet spot' for it to work.

Try it out, it's working for me now.

Right. I have the problem with my Magic Trackpad when Time Capsule backups kick in on my 13" Macbook Pro (2010 edition). The Trackpad becomes unusable as the performance stutters.

My Macbook Pro is elevated about 8 inches off of my desk by a Griffen Elevator Laptop Stand to prevent neck cramp. In addition to the trackpad, I'm also using the Apple wireless keyboard.

http://store.apple.com/uk/product/H2619ZM/A

Work-Around:

The problem appears to be the strength and placement of the blue tooth antennae in the MacBook Pro. There appears to be a blue-tooth blind-spot between the 4 to 5 o'clock angle to the right (and possibly below, as I'm using a stand) of the Macbook Pro. If I shift the Macbook so that the Trackpad is directly in front of it, the problem goes away. Likewise if the trackpad is sitting to the left of the Macbook Pro, the problem goes away (so possibly not a problem for left-handed users).

The right-side stuttering problem is more pronounced when the Macbook Pro is elevated on the laptop stand, than when it is at the same level as the TrackPad where it becomes at least usable, but still a bit noticeable.

So, if experiencing this problem, try moving the trackpad's position in relation to the Macbook Pro so that it is either somewhere directly in front of the laptop or to the laptop's left-hand side (7 to 8 o'clock angle), then once the Time Capsule backup has finished move the Trackpad back to a comfortable position.

Not the best solution, but it keeps me sane.

Sorry. What I just posted is rubbish. Please ignore. I didn't thoroughly test it before posting. Even with the trackpad to the left-hand side, I get stuttering during Time Capsule backups.

Right - This really has taken care of the problem for me. Stuttering completely gone despite backing up a 1.5GB file via Time Machine to Time Capsule. Doesn't matter where I have the trackpad positioned.

I've upped the signal strength of my Time Capsule to 100 percent and connected my Macbook Pro via 5GHz wireless. Beforehand, I had the signal strength at 10 percent and was using the default GHz frequency.

I think upping the signal strength of the Time Capsule allows the wireless on my Macbook Pro to use less power, thus allowing more power to be allocated to blue tooth. Or possibly, switching over to 5GHz has removed interference with Bluetooth.

Anyway, I'm currently 1GB into the backup and not a single stutter. Completely smooth.

Now I just need play with the signal settings on the Time Capsule to find the sweet spot.

Again, sorry about the earlier post in which I claimed repositioning the trackpad worked around the problem.

regards

Looks like it was switching and connecting to my Time Capsule router at 5GHz Wifi frequency that did the trick, for I've reduced the signal strength back down to 10 percent from 100 percent, and I'm still stutter free during backups when connected at 5GHz.

So, for me, the resolution for the Trackpad stutters was to connect to the router's Wifi at 5GHz. I guess that the higher frequency prevents Wifi activity from interfering with the Macbook's Bluetooth signal.

That's all from me. Good luck all.

Same issues here... got my first unit replaced today. 2nd unit started acting up. After reading through this thread I started playing around in my Airport utility and managed to really get it to act up as I was playing around. I have one Airport Express for WiFi and a 2nd one setup for wireless printing. When I unplugged both Express units the erratic behavior immediately stopped. I plugged them in one at a time, WiFi first, all is good. Then the 2nd printer express unit and it is working fine right now...

I'm sure it is a matter of time before it acts up again, but I as well seem to lean towards wireless interference... there we go, as I am writing this, it is back... disappointing.