QuickLook blanks when displaying some images

Solution 1:

This "blank Quicklook image" Bug is caused by the activation of the undocumented TextSelection-Feature. As soon as I deleted that feature with this terminal command the blank images were never seen again ;-)

defaults delete com.apple.finder QLEnableTextSelection; killall Finder;

If this delete-command doesn't work for you, you could try to disable the feature with

defaults write com.apple.finder QLEnableTextSelection -boolean NO; killall Finder;

Solution 2:

A temporary solution is to press ALT (twice) when presented with a grey image.

Solution 3:

I'm using Yosemite. Tried all those approaches above, but they didn't last for long. But I did find one approach that DID work. Hold down the Option key before pressing Quick Look (the icon will change). The pictures will go to full screen. Then it won't fail to display. Press Esc to quit.