Hello. Invalid DVD navigation structure is one of the many well known protections nowadays. However, there are ways to get around this issue.Well, there are tons of FREE tools that can rip any dvds (yes.. even new released) flawlessly, regardless if it's RipGuard or ARccOS. Below are some very useful FREE tools to have.<< *FREE* Ripper & Editing tools >>** DVDFAB Decrypter - one of the best FREE ripper now (takes 12 minutes to rip)** RipIt4Me - one of the best FREE COMBO/ripper including DVD Decrypter + PSL (12 - 15 minutes to rip)** VobBlanker - one of the strongest FREE editing tool (2 - 5 minutes to process/fix fake structural, fake cells, dummy vts/pgc, etc. flawlessly, it can "cut, edit, strip and blank" out any scenes/vts/cells or unwanted junks.) ** FixVTS - one of the best FREE junks processing tool (works the same way like VobBlanker, but it "can not" edit or blank out unwanted junks.)** PgcEdit - a very useful FREE editing tool. << *FREE* Transcoding tool >>** DVD Shrink - (one of the best FREE transcoding engine).<< *FREE* ISO/Image burning engines from LUK >>** DVD Decrypter** ImgBurnHere are 2 of the best FREE methods to rip movies/dvds. For more info on how to use DVDFAB Decrypter or RipIt4Me, check out the links below:Alkohol's "DVDFAB Decrypter + VobBlanker" guid "RipIt4Me" guid lucks and happy burning.