How do I get mouse zoom to work in Lion?: Apple Support Communities. The person had selected the correct options. It turns out that Thebestplacehere has the answer.
Correct AnswerRestart computer and try.
Then you can download free Snow Leopard compatible utilities here. Kinda cool. This would be most helpful for Mac users in a corporate environment with networked or remote file storage folders.
Fortunately the fix is easy. Just reboot in safe mode by holding down your shift key when you restart your Mac. Then restart your computer. It should be fixed. Click here if you want more info.
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