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new error messag

I have an"refurbished" iMac that was purchased 4/4/13.

After installing the April 30, 2016 iMovie upgrade I cannot play videos, I now am getting an error message: the system extension"/System/Library/Extensions/ALF.Kext" was installed improperly and cannot be used. The only thing I did was your upgrade!

iMac, OS X El Capitan (10.11.4)

Posted on May 3, 2016 3:46 PM

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1 reply

May 3, 2016 5:56 PM in response to annfromcorning

Your OS X installation is corrupt.

If you don't already have a current backup, please back up all data, then reinstall the OS.* You don't need to erase the startup volume, and you won't need the backup unless something goes wrong. If the system was upgraded from an older version of OS X, you may need the Apple ID and password you used.

There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

*The linked support article refers to OS X 10.11 ("El Capitan"), but the procedure is the same for OS X 10.7 ("Lion") and later.

new error messag

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