Microsoft Expression Media (Ver. 1) uses Apple QuickTime to import and play Flash Movies (SWF). However, Flash movie (SWF) playback support is NOT available in the latest version of Apple QuickTime version 7.3.1. Thus, Expression Media wouldn’t be able to import SWF movies if Apple QuickTime version 7.3.1 or later version is installed.
So, how do I import SWF movies into Expression Media? The only way to import Flash SWF movies into Expression Media is by manually entering SWF file type in custom.txt. The problem is, even if you modify the custom.txt and include SWF file type, it will just enable Expression Media to import SWF files into the catalog with a generic icon. It does not show preview or play the Flash movie in Media view; it will show "Unknown error " instead. So if your main goal is to archive/catalog the Flash movies then this option is for you.
You can modify the custom importers, as described above, on Macintosh as well. On Macintosh, you can find custom.txt at the following location:
Finder : Go : Applications : Right Click "Expression Media" : Click "Show Package Contents" : Contents : Resources : English.lproj : Plug-ins : Importers : Custom.txt
If you have Apple QuickTime Player Ver. 1.x or 2.x installed and wondering why Expression Media is still not able to import and play the SWF movies? You can import and play Flash Movies (SWF) in Expression Media by enabling following options in Apple QuickTime Ver. 1.x or 2.x:
"Enable Flash" option should checked under System Preferences : QuickTime : Advanced.
Reference: QuickTime 7 Supported Audio/Video Formats http://www.apple.com/quicktime/player/specs.html