Quick Look is a quick preview feature developed by Apple Inc. which was introduced in its operating system Mac OS X 10.5 Leopard. The feature was announced at the Worldwide Developers Conference on Jun. 11, 2007.
|Initial release||October 26, 2007|
(Mac OS X 10.5 "Leopard")
While macOS's Finder has always had smaller previews in Get Info windows or column view, Quick Look allows users to look at the contents of a file at full or near-full size in the Finder, depending on the size of the document relative to the screen resolution. It can preview files such as PDFs, HTML, QuickTime readable media, plain text and RTF text documents, iWork (Keynote, Pages, and Numbers) documents, ODF documents, Microsoft Office (Word, Excel, and PowerPoint) files (including OOXML), and RAW camera images.
Quick Look can also be opened in full screen and launched from the command line. Additionally, multi-page documents like PowerPoint slide shows can be navigated using the slide previews at the side of the preview window.
Since its debut, Quick Look has included a number of generators for common file types.
|AAC||10.5||Cover art in icon view and can play back audio in full preview.|
|Apple Icon Image format||10.5|
|Cinema 4D's .c4d||Displays the 2D Preview Image embedded in the file.|
|GIF||10.5||Did not animate animated GIFS without additional plugins until OS X 10.7.|
|HTML||10.5||Does not load remote resources or execute scripts.|
|MIDI||10.5||MIDI files support has been dropped in OS X 10.8.|
|MP3||10.5||Cover art in icon view and can play back audio in full preview.|
|QuickTime movies||10.5||Additional stream formats require the appropriate QuickTime extension to be installed.|
Plug-ins can be added to Quick Look to allow previewing the content of other file formats. Plug-ins can also be used to add additional functionality to Quick Look such as syntax highlighting for source code files.
To add a plug-in to Quick Look it needs to be placed in the folder
/Library/QuickLook/. To activate that plug-in, either the computer needs to be restarted or Quick Look needs to be reset with the command
There are multiple ways to invoke Quick Look.
qlmanage -p file
Quick Look can be exploited when conducting a forensic examination of a computer's contents. A thumbnail cache is created for each user in a random subfolder of
/var/folders called com.apple.QuickLook.thumbnailcache. The cache contains two files;
Quick Look thumbnails are stored for documents on internal disks and also for documents located on removable disks, including those that have been encrypted and can pose a significant security hole. A document may well have a number of thumbnails, each having different dimensions that can range from very large to very small.
The cache can be reset by invoking the
qlmanage -r cache command via a Terminal window.