One way is to look at the packaging of the disc or on the upper side of the Disc on the label. So far, afaik all discs with a region lock I encountered , at least have it noted on the packagaing and/or on the disc-label what region lock is on the disc. Some region-free discs have ABC marking on the box and/or disc-label. Other (afaik region free discs) didn't have any marking noted on the box nor on disc-label, afaik they are region free, too. Not sure, but I'd guess but I think I saw a disc also with region code, without any notification. I chose player-B-emulation in AnyDVD. Also never got discs here from other regions. To find out the disc region, when it's not noted, if AnyDVD has bad luck here to find out the region, I'd guess the developers can't help, otherwise it would be possible to have it already implemented in AnyDVD. A+B+C disc (region free) note on the disc surface. -- I can't say how AnyDVD does it, but I know a program called "UltraISO". E.g. in UltraISO you can modify an UDF filesystem (like Blu-ray has), without extracting ISO-content to get modified iso and without the need to repack it. Maybe AnyDVD uses similar way to replace or modify some Java jar-files on the fly or put replaced ones in UDF file system. "UDF parser", don't know. Also you can hide files in UDF, as if it was deleted, and it's still reversible (toggable) You can copy/delete files/directories here, move and rename the directories without repacking it. Obviously this is possible with UDF filesystem. Also tested this in Linux mounting an ISO as writable. The write-moutning didn't work in first place. First had to mount the iso normally as read-only and then remount it is rw. /media/ISO <=mountpoint 1)mount -o loop *.ISO /media/ISO 2)("mount -o remount,rw *.ISO /media/ISO" .) It worked editing the ISO in Linux (e.g. renaming some files in it) But Virtual Drive Software in Windows no longer could mount that edited ISO (Alcohol 120%), but didn't test with Virtual Clone Drive - only Linux could still mount the modified ISO. @markfilipak. At least this might confirm modifying on UDF-filesystem-level, as "virtually" mentioned =>Virtual Drive - Blu-ray has UDF 2.5/2.6. When AnyDVD can circumvent AACS I think it should be able to interfere on UDF filesystem level with the region-chech files in the disc's filesystem, virtually altered.