http://www.imdb.com/title/tt0166924/fullcredits doesn't match the actual credits

I don't know the film well but there seems to be greatly differing versions of the film. With a large difference in running times, there certainly might have been a difference in on screen credits. The credits for a film's page should reflect credits during its original release.

Thanks bluesmanSF, but I doubt it. The running times match: 147 min v. 2:26:53, and my DVD (UPC: 025192178023) was released on April, 9, 2002 (see http://www.useddvd.com/46606/mulholland-dr-used-dvd.html). I think it is the original release, and that it's highly unlikely a unique cast credit would have been made for it. Probably, someone embellished the cast credits based on what they knew about the 1999 TV pilot. Should I pursue this further?

It's original release was a year earlier at film festivals and theatrically. Not on DVD. You might wait to see if anyone can shed more light. But, the DVD credits are not what they'd have verified it against. At this time, it'll be difficult to find a way to check it. So, this is why they verify then mark them complete which bars further change without very good proof (and in this case, a DVD release wouldn't likely suffice, I'd guess).

Yes, it'd be worth asking on the title's message boards before submitting changes. We've seen a number of examples where at least one of the home media releases differs from the theatrical release credits and people have "corrected" the right credits with later ones. So you need to be sure.

Oh, my! Thanks guys. (What a nasty problem for IMDb.) May I suggest an architectural change to the IMDb: Multiple cast lists, one for each media. I know what a pain in the a** that would be, but there's really no better alternative... Or is there? As things stand, I'm not going to bother checking such stuff in the future because I'm unlikely to view an actual theatrical release, and even if I did, it might be different from the original theatrical release ...How would one know? Answer: without a time machine, one can never know for sure.

Thanks guys. (What a nasty problem for IMDb.) May I suggest an architectural change to the IMDb: Multiple cast lists, one for each media. I know what a pain in the a** that would be, but there's really no better alternative... Or is there? Well I quite like the idea of being able to list home media releases, as some directors cuts include people not seen in the theatrical release (the opening scenes of Aliens, for example) and you could also then include dubbing from different countries (at the moment you can only list the American dubbing for anime, for example, but there are oddities out there, like the UK release of... Cars I believe having the American cast except for... Jeremy Clarkson/Jonathan Ross dubbing one character, which is worthy of note). It'd be easy enough to do as you'd only need a "parent" field for the ID of the original theatrical release and they have the feature for copying cast and crew across from TV series. Has anyone made a suggestion along these lines? As things stand, I'm not going to bother checking such stuff in the future because I'm unlikely to view an actual theatrical release, and even if I did, it might be different from the original theatrical release ...How would one know? Answer: without a time machine, one can never know for sure. Thing is, you've got to do the best with what you have to hand, but if you are verifying a cast and crew list and there are discrepancies, you've got to ask yourself if you are sure you are working with something that is the same as the theatrical release. I suppose this is where the very early pirated copies come in handy ;) However, as long as you aren't working on an extended cut, it is going to be a rare problem - it has come up once on here, where the DVD release mysteriously left a section of the credits out for no obvious reason. The main place this seems to come up is with Les/horn on the CH forum running into people doing things like working from TV edits of older western films which had new titles made for them, but you should be awfully careful about doing things like that and you have to know the subject area. Which is why I stick to adding titles and fixing obvious problems, and steer clear of verifying anything. So not a reason to throw up your hands in defeat over, but just something to bear in mind when being gung ho about editing perceived problems - if in doubt ask, someone should be able to help.

I don't agree with the assumption that IMDb's cast list must be from the original version. It has been brought up many times by experienced contributors that there are mistakenly verified cast lists in IMDb. Bringing it up here is the right thing to do, but the reply needed would be for IMDb to look into their records and decide if there is any reason to think their version is correct.

I downloaded this: https://archive.org/download/HisGirlFriday-1940/CaryGrant-1940-HisGirlFriday.mp4 and the credit roll at the end doesn't match the IMDb cast list for His Girl Friday. Are you going to tell me that someone sitting in a theater in 1940 wrote the cast list for IMDb? Or are you going to tell me that someone made a new credits roll and attached it to the archived public domain version? The cast list for His Girl Friday says "Cast  (in credits order) (verified as complete)" Nonsense.