I've just tried to save a Movie Maker Project as a video and it tells me that the file may be corrupted or that it's not supported.

The video file I'm trying to save is an M2TS file, which from what solutions I've been searching through is supposed to be unsupported by WMM. The thing is though, I've edited and saved numerous M2TS files with Movie Maker before and it has never once given me an issue. This file is no different than the ones I have previously saved but all of the sudden it's unsupported?

I don't suppose there's any possible way to convert the project as is instead of having to convert the original footage and then re-edit the entire thing again?