4 Replies Latest reply: Mar 16, 2013 1:43 PM by baltwo
Marc Marshall Level 1 (45 points)

I've now had the same really strange pair of two seemingly unrelated issues show up on two different Macs, one a client final-gen white MacBook, and the other a first-gen C2D Mini.  Neither has much in the way of 3rd party stuff installed, so I'm kind of at a loss as to what's causing the behavior, and was trying to pin it down before resorting to a wipe and reinstall in an attempt to fix it.


The two things that happen are:


  • The cursor, when clicking, will occasionally "flicker" over to the side by an inch or two.  It always pops back to where it's supposed to be, and clicks don't register in the wrong place, but you can clearly see it briefly flickering in the wrong location.  Sometimes it's fine for a while, sometimes it will do it every time you click.
  • The computer will periodically beachball for about 5-10 seconds, despite there being very little CPU activity, plenty of free RAM, and not much disk activity.  It seems random, and there seems to be no correlation to any system resource use.


Both systems are running 10.6.  The MacBook has no external peripherals at all, and the Mini has a 3rd party wired mouse and Apple wired keyboard.  There are a few 3rd party applications and pref panes (Flash, for example) installed on both, but nothing that I haven't seen installed on dozens of other Macs without issues.  Hardware Test comes up clean, disk checks are fine, permissions have been repaired, PMC resets done, etc.


Has anybody seen behavior like this?  Suggestions of what to try apart from OS reinstall?

  • baltwo Level 9 (62,215 points)
  • Marc Marshall Level 1 (45 points)

    Thanks for that link, baltwo, but I probably should have clarified that I provide IT for a dozen Macs in a small office as well as freelance support, so I'm aware of, and have checked for, all the standard beachball causes twice over.


    The only reason I even bothered posting was the cursor flickering symptom.


    The unexplained beachballs (again, they occur randomly across apps, and do not correspond to disk access, RAM shortage, paging, or high CPU use), while more annoying to the users, are actually the secondary diagnostic symptom as far as I'm concerned; the cursor is much more specific and seems to point to SOMETHING messing with either mouse input or cursor positioning, despite there being nothing on either system that should be doing that.

  • Marc Marshall Level 1 (45 points)

    I figured out what was causing the weird flickering cursor, and I'm now somewhat surprised I haven't seen more complaints about it:  Adobe Acrobat/Adobe Reader.


    I've tested on nearly a dozen different 10.6 systems at work, family, and clients, and every single one has displayed the same symptom when either Acrobat (8, 9, or X) or Reader (9, X, or XI) is running and active or there is a PDF being rendered by Adobe's Safari plug-in (as opposed to the Apple one).  Opening an Adobe preferences window is guaranteed to trigger it, but it'll also pop up randomly.


    I now realize the seeming randomness of it was due to the people seeing it having either PDFs open in Safari and my not realizing it, or Adobe Reader running.


    The beachballs were a red herring; they may have been caused by the same thing on the two systems I was working on (both cleared up without me ever pinning down a definite cause), but they had nothing to do with the twitchy cursor.

  • baltwo Level 9 (62,215 points)

    Thanks for the feedback. I've disabled Adobe's PDF plug-in and use Schubert's instead.