I recently got two new Macs, an iMac (with magic trackpad) and a MacbookAir (both the most recent models - mid 2011 and both with Lion). They are both suffering from the same issue so I don't think it's hardware based.

Basically approximately every 10 or 15 minutes I'll be trying to move the mouse pointer or click and suddenly the pointer will jump to the corner of the screen (normally the bottom left but sometimes the top right). It might do it three or four times in a row and then not for half an hour.

I wondered if it was some sort of gesture I was accidentally performing (maybe more than one finger is touching the trackpad as I click?) but I don't seem to be able to reproduce it on purpose. It doesn't seem to be tied to one particular app but happens whatever I'm using.

The only mentions of a similar problem I could find online talked about hot corners and I've made sure all hot corners are disabled in system preferences.

Has anyone else run into this? It's driving me absolutely crazy (because when I click in the bottom corner the active app loses focus and I lose my flow!).

Edit: to add further information which may help.

I started to suspect that it might be something to do with applications that I have running all of the time. So I started trying to change things (as much as I can while still being able to work). The first potential culprit was Terminal running in fullscreen mode. So I took it out of fullscreen mode. And for a while it seemed to fix the problem. But unfortunately it is still happening but it appears to be less frequent!

I don't have anything else running fullscreen and I also don't have Dashboard running in a space (the problem still happened when it was).

Other apps that I am prettymuch always running:

  • Alfred (launcher)
  • PhpStorm (IDE)
  • Firefox

Does that help at all?

Edit: Another update.

At the suggestion of @mspasov I checked the logs in Console.app just after it happened. Unfortunately there doesn't appear to be anything that shows up in the logs at the point when the jump happens. I warnings like this:

osascript: Error loading /Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types:  dlopen(/Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types, 262): no suitable image found.  Did find:
    /Library/ScriptingAdditions/Adobe Unit Types.osax/Contents/MacOS/Adobe Unit Types: no matching architecture in universal wrapper

But that is happening frequently and happens lots of times when the jump doesn't.

Trying to think of software which could be causing the problem it suddenly occurred to me that Growl is also constantly running on both machines which display the problem. However, disabling Growl hasn't stopped the problem from happening...

  • I have seen this on two very different macs (2009 iMac and 2010 15" MBP) that run very different software stacks. The iMac is 100% apple - aperture, safari, iTunes and no third party apps. It's mouse pointer jumps very often - even when the mouse is off and I'm using the Magic Trackpad. I think something Lion is up, but can't pinpoint it yet.
    – bmike
    Commented Oct 10, 2011 at 22:10
  • Do you have some kind of a screen sharing software? Is there a slight possibility of something messing you via VNC?
    – mspasov
    Commented Oct 11, 2011 at 10:36
  • Thanks for the confirmation @bmike. Just to confirm you see the jumping all the way to the corner of the screen?
    – vitch
    Commented Oct 11, 2011 at 14:09
  • Thanks for the suggestion @mspasov but I haven't installed VNC or any other screen sharing software. I do have Skype (the old 2.8 version) installed but the problem happens when it's not running. I've never knowingly activated the OSX native screen sharing either.
    – vitch
    Commented Oct 11, 2011 at 14:11
  • Ok. Can you check your logs (Console.app) for any event happening when the jumping occurs?
    – mspasov
    Commented Oct 11, 2011 at 19:18

2 Answers 2


The mouse problem you are suffering from has to do with OS X polling rates. It has been a known issue for quite some time now. You can read about the issue and a general rundown of some of the mice affected.

Note that contrary to what the author states, the problem still very much exists in OS X Lion. Refer to this post for your specific problem, which identifies CPU cycles as a possible culprit.

As a designer, I found this insufferable. I purchased and tested (even Apple's Magic Mouse) numerous mice only to have them returned to the store. Each mouse worked flawlessly under Windows 7 I might add. I ended up buying a Razor DeathAdder (Black Edition) with ample DPI and polling rate (even though I don't game). It still jumps every know and again when the CPU is busy (I'm running a more than capable Mac mini 2.3 GHz i5 with 8 GB of RAM and an OCZ Vertex2 SSD) but the jumps are so extremely infrequent that they are now a rarity rather than the norm. I should note that this problem occurs using the native OS mouse drivers, the Razor factory driver, or SteerMouse.

Sadly, there is truly no solution, just workarounds (mine was to buy a mouse with industry leading polling rates and DPI.

The simply truth is there is a flaw in OS X and how it handles mice that needs to be fixed. And Lion has not corrected the issue.

  • 2
    The only time I've ever had this issue, with any/every mouse I've ever used, was when I used a poor mouse surface. Be it a dirty mouse pad, a noisy (multi-color/spurious edging) mouse pad, or just straight on a desk top or other surface. Commented Sep 27, 2011 at 0:19
  • @VxJasonxV believe me, it has nothing to do with the surface. I've used mice on my desk (smooth, dark wood grain laminate) that have skipped, only to have plugged them into a notebook running Windows 7 and watched them glide smoothly right on my beige carpets.
    – user10355
    Commented Sep 27, 2011 at 3:29
  • 1
    Thanks for the answer but unfortunately I don't think this is what is effecting me. In my case the mouse jumps half way across the screen. I'm normally interacting with something around the middle of the screen and it jumps to the bottom left corner. It always seems to jump just as I click and so focus is given to the background item. It also doesn't seem to be dependant on CPU cycles as both new computers have fast CPUs and I'm not working them too hard. I'd be surprised if it was hardware since it is happening with an Apple Magic Trackpad and the trackpad in the MacBookAir...
    – vitch
    Commented Sep 27, 2011 at 9:34
  • Did the polling rates change with Lion? (if not, then some other processes are interrupting much more often) I'll also chime in that the surface can't be causing it as I get jumps when nothing is moving - no earthquakes, no desk bumps - just the pointer on the screen)
    – bmike
    Commented Oct 10, 2011 at 20:52
  • @bmike I don't think so. I don't see any changes in the way Lion handles mice compared to SL. Even my Razer skips a few microseconds when my monitor comes out of sleep. Or when some programs are launched for the first time. The Razer makes the annoyance a rarity and more than bearable but it's still there (just on a much smaller scale). My Logitec MX is another story. In fact all regular mice I've tried are unusable to me.
    – user10355
    Commented Oct 10, 2011 at 21:26

If your preferences are corrupt, you could delete anything in ~/Library/Preferences/com.apple.driver.AppleBluetoothMultitouch* and log out and then in again to start with new MultiTouch settings to see if that fixes things.

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