Exporting OMF - "Unable to Open A Required File"

If you are going to embed the audio, the total file size can't go over 2GB, and sometimes on big projects that's not much of a limit. If that's likely to happen, then the thing to do is to use the separate audio option. Yeah, not quite as neat but could get you out of trouble. But as a check, that may well be worth trying anyway if you aren't already doing it. Other things to consider are where the file you are trying to include is stored. If the OMF generator requires immediate access to a file and it's stored remotely and not available at the absolute instant it's required, then this is the sort of message you're likely to get. The answer to that is simple; make sure that all the files you want to include are stored on a local drive, and if it started out as a compressed format, that the copy that was decoded is the one that's available for the OMF - I'm pretty sure that the files have to be in the working format before you can include them.

I can't think of anything else obvious, though.