I've nothing whatsoever against a 2.0 stereo or discrete surround remix being created for a film which had a mono original theatrical release soundtrack, as long as both are included on any DVD/BDs. If done well, and particularly from original stems, the results are usually at worst interesting and at best, surprisingly good. For the record I tend to watch with the original mono by myself, in multi (non-discrete) surround mode, and play the discrete surround mix when viewing with friends and family. If the mono is included on disc it's often downgraded to a lossy Dolby Digital track but that's acceptable. On Euro releases mono OSTs are often left off, where the US equivalents include them, which is inexcusable. At least then I can go to the extra effort and expense of buying the US BD. I really object, however, when it's not included at all. There are any number of DVDs where this occurs but can you give examples of BDs which do this? I specifically mean instances where the mono track isn't available on any BD worldwide. Naturally I'm not including mono downmixes of the remixed track... A few that spring immediately to mind, are: Earth vs the Flying Saucers (1956) 20 Million Miles to Earth (1957) The Magnificent Seven (1960) Quatermass and the Pit (1967) King Kong (1976) The Terminator (1984) Can you supply other examples? Edit: ok, based on the suggestions so far here's an amended list: Airplane! An American Werewolf in London And Justice for All Animal House The Apartment The Aristocats Barry Lyndon Billy Jack Blazing Saddles Body Heat The Breakfast Club (unconfirmed original mono) Caddyshack The Cannonball Run Cannonball Run II A Clockwork Orange Dead and Buried Dirty Harry Earth vs. the Flying Saucers The Enforcer Enter the Dragon The Evil Dead (1981) The Evil Dead II (1987) Excalibur The Exorcist Fast Times at Ridgmont High Friday the 13th: The Final Chapter Friday the 13th: A New Beginning Full Metal Jacket [Halloween (1978) – 2007 BD: DD orig. mono; 2013 35th Ann. BD: DD mono downmix of 7.1 remix; 2014 box set-only 35th Anniversary BD: corrected Dolby TrueHD orig. mono] High Plains Drifter Jeremiah Johnson The Jerk Kramer vs. Kramer Mad Max (1979) – BD mono and 2.0 stereo tracks: downmixes of 5.1 remix The Magnificent Seven (1960) Magnum Force The Manchurian Candidate The Many Adventures of Winnie the Pooh Meet Me in St. Louis Midnight Cowboy The Naked Gun North by Northwest The Odd Couple One Flew Over the Cuckoo's Nest The Outlaw Josey Wales Quatermass and the Pit The Rescuers Robin Hood (1973) The Shining (1980) Silver Streak Singin' in the Rain Sixteen Candles Smokey and the Bandit Some Like It Hot The Sting Straw Dogs Sudden Impact The Sword in the Stone The Terminator (1984) Three Days of the Condor THX 1138 Trading Places 20 Million Miles to Earth The Warriors Westworld Willy Wonka and the Chocolate Factory (1971) Are there any more? NB: There are many more films that, while they have 'original' mono audio on the BD, it's actually a restored or reconstructed track, composited from original elements. One of these is The Wizard of Oz redone 1998 soundtrack, mentioned by Eric below. Attempting to list all such examples would be fairly pointless, not least because almost all original audio has some work carried out on it for home video or theatrical re-release. Determining the exact provenance and 'authenticity' of every mono track would be an extremely difficult, not to mention highly subjective, exercise. The Blu-rays With Missing Elements in the Primary Audio Track thread is more useful in this regard.