This entry is a self-note, an answer I struggled to find for quite a while…
Open source projects: please don’t rename stuff in the API without updating the documentation. It causes grief! :)
I finally found it and I’m going to share this with you :)
Being able to preview videos within Quick Look is practical but it takes unnecessary CPU power while trying to create the thumbnails for the videos in Finder. You can disable the thumbnails but you want to keep the thumbnails of images. Here’s the solution:
In Finder, choose Go from the toolbar then Go to folder. Open the folder
/System/Library/Frameworks/QuickLook.framework/Resources/Generators/
copy the file Movie.qlgenerator to some other place then delete it. You will be asked for you password.
When you restart your Mac, movies won’t have thumbnails anymore and won’t start playing within Quick Look, they’ll behave like normal files.