This trick alone can offer a significant performance boost to Macs as we’ve mentioned before, particularly for older models, those without SSD drives, or those with less available RAM. This setting change is immediately visible whether any folder is using the icon view, list view, or column view, all icon previews immediately disappear: Uncheck the box next to “Show icon preview”, then to apply this to change to all folders click the “Use as Defaults” button.Open any Finder window other than All My Files, and pull down the “View” menu, choosing “View Options”.This is easy to do and will stop all icon thumbnail generation of folder contents: Turning Off Icon Thumbnail Previews in OS X Finder In other words, system resources will only be used when Quick Look is activated on the files in question, not simply when opening a directory.

Note that neither of these settings will impact the functionality of Quick Look, letting you still easily scan through pictures but having more direct control over what is loaded and when.

Disable folder preview mac os x