Mac now adds noise that look like stars

[GOTO]

Hello all,
Until a few weeks ago I could take wide field images and happily process them in Lightroom 4 apart from RAW images taken on my 6D. So, I updated to Lightroom 5. Since then whenever I open an image in finder, the image looks fine for a second or two and then almost fills up with noise that just looks like thousands of extra stars. I can't explain it and wonder if anything like this has happened to anyone else?
Regards
Geoff

[Poita]

Not having the problem here with RAW files from my Nikon.

Maybe try loading RAW files from another camera and see if you still get the problem?

[GOTO]

Hi Peter, RAW images from my 550D are fine in Lightroom 4 and those from the 6D only in Lightroom 5. It does look like its restricted to files I've opened in Lightroom though.
Geoff

http://i39.photobucket.com/albums/e185/Tokyo1989/ScreenShot2014-08-20at82636pm_zps1d35e86b.png