Elementary streams are an MPEG variant that we can't open reliably, so we don't allow it.
Since you created the file in Vegas in the first place, a better option would be to go back to the project you used to create the .m2v and re-render from the original source material. The quality will be much better-
Thanks for your reply. What I wonder about is whether I have to keep the .mpg file that sourced the vob that sourced the DVD or if a future version of Vegas could load .m2v files, could I just demultiplex the vob and load the .m2v? It's not always feasible to hold on to the original tape and if you've got to hang on to the .mpg, it just doubled the cost of the DVD since you need another disc to hold the .mpg archive of the file. A for instance could be that I made a DVD in which a bad edit crept in. I didn't notice it until I erased the DV and the .mpg because of storage constraints on my hard drive. I therefore only have the DVD from which to get my footage for re-edit.
It can be a hassle, but keeping the original source material, or at least copies, is the best practice if you think you may need to re-edit at some point.
I'm just curious about one things. You said that Elementry Streams could not be opened reliably but every DVD authoring app out there seems to be able to do so! So, by reliably, do you mean just from within Vegas, or in general? I'm not complaining because Vegas never advertised that it could open this type of file, I'm just interested in where the issue really is.