The Lion and the Jumpy Mouse: A Mac Users Tale of Frustration

Immediately after installing Lion I encountered the problem and have been researching it since. I thought I had fixed the problem by turning off pointer acceleration, but unfortunately that just reduced the symptoms.

My experience:

I first noticed that my mouse pointer will jump around the screen while moving it. That is, I would move the mouse a short distance but it does not move (seems “frozen”), then appears on the screen having covered a greater distance than it should have (100px move, appears 250px away [arbitrary values]), with no movement animation.

This seems to happen when various components in my system are under some sort load. It reminds me of older PCs and how human interface devices would take a back-seat when the system bus became overloaded.

I have noticed the problem occur during the following system activities:

  1. Dropbox displaying a growl notification about files being removed from my system (Growl, video, disk?)
  2. Saving out files in photoshop (video?, disk)

What I know it is not:

1. Solely Disk I/O related. I have run a command like “dd if=/dev/random of=/tmp/largefile bs=1024 count=4000000” and moved the mouse all around the screen.
2. Solely video-related. I can play games just fine, though the pointer does become noticeably more jumpy.

I expect the problem is related to multiple components.

My current system configuration:

  • 21″ iMac (Mid-2010)
  • 8GB ram
  • Additional 20″ monitor (mini-to-dvi adapter)
  • Logitech MX518 mouse
  • Apple USB keyboard
I’m going to continue revisiting this until I’ve figure out what’s causing the problem.

Mike Walker

Mike is a full-stack web developer with 15 years experience. I focus on PHP & Javascript development, and work with platforms like Shopify Plus and WooCommerce eCommerce. The Agency Developer is a weekly curated newsletter with a mission to inform and educate developers working with digital agencies.

This Post Has 19 Comments

  1. Had exactly the same problem with an external USB mouse, and it was solved immediately by disabling FileVault full disk encryption.

    FileVault with full disk encryption was introduced with Lion, that could be the reason why the problem seemed to have emerged along with Lion.

  2. Just wondering if anyone knows of a solution to this problem. I have a Mac Mini 5,1 with Thunderbolt display running Lion that definitely has the issue with my Logitech Trackman trackball as well as other USB mice, but ONLY when iTunes is running. I tried creating a completely new user account, but it had the same problem. I hate to have to reinstall from scratch to see if the problem is in the system preferences somewhere!

    1. Honestly, the more I learn and the more I experience the problem, it seems like whenever an App is “syncing to the cloud” the problem raises it’s ugly head. Maybe when iTunes is syncing/backing up, or dropbox is doing it’s thing. I’m still not sure. :/

      1. I’ve also noticed occasional stalls and glitches when changing from space to space or activating Mission Control on the Mini (but not the Air), which make me suspicious that the graphics or the bridge chipsets are really to blame.

    2. Reinstalled from scratch; problem still occurs. I don’t think the problem is “syncing to the cloud”; the new install and account were NOT connected to my iCloud accounts, Dropbox, or any other syncing. The problem doesn’t seem to occur on my mid-2012 11″ Air, though; just the Mini. If it’s a hardware difference, though, it could be anythiong; the two computers are basically completely different inside. (Maybe it’s just an artifact of the pre-Ivy Bridge chipsets?)

    3. I have found a solution to this problem; upgrade to Mountain Lion. I upgraded today, and since then, no jumpy mouse.

  3. It happens on my new Mac Mini (Mid 2011) that I just got. Strangely it doesn’t effect my Mac Mini (Late 2009). Both Macs uses Lion OS. The jumpy mouse happens when QuickTime or/and iTunes are launched and the CPU usage spikes up between 100% and 230%. After quitting them, the mouse goes back to normal. As long as the CPU usage level is below 100%, my wired Mighty Mouse behaves normally. What causes the CPU spike is the QuickTime related. It’s either its extension, preference or somethings else that needed to be fixed.

    1. After updated to Mountain Lion, deleted QuickTime 7 Pro, and deleted, it cures the jumpy mouse. QuickTime X does not cause any problem.

  4. Happy new year — It’s still happening on my 24-inch Mid 2007 iMac with dual monitors. I have a wired Logitech laser pointer. The problem is not so bad that the pointer will jump all the way to the corner of the screen, as some describe, but the pointer tracking isn’t smooth any more. It’s like the old ball mice when they got dirty. Very annoying.

  5. Many people have complained of similar issues; please see the full thread at

    At the suggestion of users in the thread linked above, I have resolved the my “jumpy mouse” issues by unplugging my second monitor and rebooting. Obviously this is a work-around and not a solution, as I now have a blank monitor sitting next to me.

    I still believe the issue is one related to mismanaged hardware resources in Lion, because:

    1. It worked fine in Snow Leopard.
    2. Dual-monitor support was terrible when Lion first launched, who is to say that they’ve resolved all the issues?
    3. It affects devices that would use the internal system bus (USB, bluetooth, etc).

    I am not intimately familiar with the hardware architecture of Apple machines, but here’s my best guess of what’s technically happening:

    Secondary displays (connected via DVI) are running through the “southbridge” of certain machine builds, I believe. If this is the case, the southbridge bandwidth is likely becoming saturated when having to deal with a second monitor being connected. This makes sense as the “hang ups” we experience don’t seem I/O or computationally related; I don’t have my disk activity or network connections drop when I experience the problem.

    Since we can now pin-point and work around the problem, what we need to do now is LET APPLE KNOW. I called support but they suggesting using the feedback form located at the link below.

    Apple feedback link:

    If everyone on this thread submits feedback we’ll have this issue resolved much faster!!!!

  6. I occasionally have this too. The only pattern I have noticed is with Chrome and having a multitude of tabs open with one website taking a long time to load. Normally closing the offending tab or restarting the browser cures the problem.

    Activity monitor doesn’t show up anything out of the ordinary for what I may be doing at the time either. So that doesn’t give much indication.

    I also have dbox, textexpander and various other programs constantly running in the menu bar etc.

  7. Same problem…I thought it was my lack of coordination. Mid-2007 24 inch iMac with Apple bluetooth KB and Apple Tragic MackPad.

  8. No real updates yet guys, but I did want to mention that I had the pleasure of using a Jambox this afternoon! Great little device, but when I hooked it up to my iMac via bluetooth the music would spit and sputter in a similar fashion to how my mouse jumps around. I believe the issues are related. Sigh.

  9. Mike, I have the same problem. 2011, 17-inch MacBook Pro that I have hooked up to a 21-inch monitor and wired Mac keyboard. I’ve tried a Magic Trackpad, a Magic Mouse, the older Magic Mouse, and the older wired Magic Mouse. ALL jump around from time to time. It’s terrible. Please advise if you find a fix. Thanks.

  10. Same here but I have the apple bluetooth mouse with multitouch so hopefully apple will have to do something sooner or later.
    It feels like my 8 core mac pro is slower than a 133MHz windows 3.1 machine….
    really annoying

  11. I have only apple input devices and Im having the same problem. Mostly when the Parallels prl_vm_app is on top of the activity list.

  12. Hi Mike,
    I encountered the exact same problem. If you stumble over a solution, please let me know. I’ll do the same.

    1. Will do! I fear it’s related to device drivers for certain types of mice. Apple likely won’t do a thing about it, so it’s up to the Vendor. Sigh!

  13. I’m experiencing the exact same issue. I’ve got a 17″ 2010 Macbook Pro w/ Nvidia 330m video card. I’m using a Razor Diamondback 3G USB mouse. I tried disabling cursor acceleration, that only reduced the symptoms. This is really bugging me.

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