Apple has released another update to Quicktime that should be a small bit of good news to unibody MacBook and MacBook Pro owners. Bringing its version number up to 7.5.7, the new Quicktime removes the HDCP playback restrictions from standard definition movies purchased and rented from iTunes. According to the release notes:
This update is recommended for owners of MacBook, MacBook Air, and MacBook Pro with Mini DisplayPort. The update addresses an issue where some standard definition purchases from the iTunes Store do not play on some external displays.
It should be emphasized that this only resolves issues with standard definition versions of purchases. So, if you were having troubles before and are now hoping to watch that download in all its high definition glory, you are still out of luck.
The update is currently only available via Software Update for all Mini DisplayPort equipped systems.