In legacy versions of OS X (e.g. Snow Leopard), QuickTime supported third-party video components. For example, it was possible to play files encoded with the UT Video codec by copying the third-party utv_qt.component to either Library/Components/ or Library/QuickTime/.

Both folders existed by default in the root Library folder (although not in the user Library folder).

What is the difference between these two folders? Are they, in fact, completely identical? Should I prefer to keep third-party QuickTime components in one location over the other?

(I've created my own QuickTime component to play HEVC and VP9, and I want to know where to recommend other users install it.)

1 Answer 1


The documentation for the directory structure is at https://developer.apple.com/library/archive/documentation/FileManagement/Conceptual/FileSystemProgrammingGuide/MacOSXDirectories/MacOSXDirectories.html#//apple_ref/doc/uid/TP40010672-CH10-SW1

(Note this document seems to be still current although it is in an archive directory. Apple decided to change their documentation format but the new one does not allow conceptual documents like this so you have to look in the archive)

Library/QuickTime - Contains QuickTime components and extensions.

Library/Components - Contains system bundles and extensions.

So either is correct.

The older document that this replaced has a revision note that information in Library was changed in 2006 and it itself replace a document in 2003. As Apple has changed the web addresses I can't find the earlier versions.

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