8 Replies Latest reply: Apr 25, 2013 7:34 AM by Marilyn Muckerman
lummis Level 1 Level 1 (0 points)

This refers to a 2011 27" iMAC upgraded from Snow Leopard to Lion. The upgrade seemed to go smoothly.


Sometimes the display jumps back and forth horizontally for a few seconds. It moves about an inch or so, not just one pixel. While that's happening the cursor is visible but the magic mouse doesn't affect it.


It usually happens while I'm editing text and I'm using the mouse to move the cursor to a new place in the text. However, I'm almost always editing text so I can't be sure it's associated with that. I use the iMAC for software development. I never play music or videos.


Do other people have this problem? Can anybody say why it's happening? Is there a way to keep it from happening?  In mouse preferences all the options are checked, which is the setting I want.

iMac, Mac OS X (10.7)