So I'm preparing to export some OMF's for a mix this week, but I'm fairly new to this part of post and when I export the sequence from FCP 7, my OMF file exports as a plain text file. Now, forgive me if this is a silly question, but is this correct? I'm not too savvy with audio mixing, but I guess at first I thought it was weird that the file exported as a plain text file, though the extension is .omf
Do yourself a favor immediately and get Automatic Duck Pro Export. This solves a nice bug that was never fixed in FCP7 where 23.98 OMF exports show up as 24.0 in Pro Tools and lots of subsequent drift errors occur.
The instructions for making an AAF from Pro Export are easy and your audio mixer will thank you.
It is not uncommon for a computer to report file formats that it has no software associated with it to display as a text file. It isn't. An OMF is a big file - up to 2 gigs and has audio and timeline data embedded in it. On a computer with appropriate software to unpack that file as an audio project the file will show correctly.
Don't bother trying to open in in a word processor.