I recently had an issue where QuickLook was crashing every time I clicked on certain file types. I thought they were unsupported by QuickLook. But it turns out that they were animated and trying to start while the QuickLook animation was starting. So disable the QuickLook animation and the files appeared as intended. To do so, write a key called QLPanelAnimationDuration into the global defaults database, with a -float value of 0, as follows:
defaults write -g QLPanelAnimationDuration -float 0
