
Unfortunately, the new security system - System Integrity Protection (SIP) of Mac OS X El Capitan, prevents applications from modifying protected files and folders. Libdvdcss, a part of the VideoLAN project, is the open-source library to unlock DVDs with Content Scramble System (CSS).

Then, how to fix that HandBrake won't rip DVD on Mac, according to different scenarios or symptoms.

But errors happen frequently in media processing, like HandBrake not ripping entire movie, no valid source found, failing to extract subtitles, libdvdcss not working, etc. HandBrake is an excellent video transcoding app, enabling you to convert videos and DVDs on Mac.
