Hi LightTrails,
Sorry to hear about the trouble you're having. Please check to make sure you're on the most recent firmware, as the firmware is often updated to include support for newer features in some films. Here are instructions on how to do so: http://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?idx=38089&modelname=BD-C5500&modelcode=BD-C5500%2FXAA
If the problem persists, try a reset: http://support-us.samsung.com/cyber/popup/iframe/pop_troubleshooting_fr.jsp?idx=149160&modelname=BD-C5500&modelcode=BD-C5500%2FXAA
HD Tech
I just recently noticed that the dvd's are laggy when played on my BD-c5500 Blu-ray player and when I skipped back and played the part again that lagged, it then worked fine. Just wondering if this can be an issue with some players? Thanks

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