MacFixIt readers are reporting, and we have confirmed in-house, that an MPEG-2 component in QuickTime 6.4 expired on December 14th, leaving users without the ability to playback MPEG-2 files.
So far, the only identified workaround is to set the date back to December 14th, a procedure that compromises scheduling tools and other applications. Also, based on all the information we have received, it makes no difference which Mac or which version of Mac OS X is being used. The problem also has nothing to do with when the MPEG-2 component was purchased.
There are two ways to obtain the MPEG-2 playback component of QuickTime - purchase it standalone and download the package from Apple's Web site or receive it alongside Final Cut Pro 4 or DVD Studio Pro 2.
Apple has a Knowledge Base document explaining how to download an updated version of the MPEG-2 component with either ownership scenario, but there is no indication that the currently available version fixes the expiration bug.
UPDATE Several readers have noted that QuickTime 6.3, released in June, will still play MPEG-2 files with the date set accurately.