yeah I had exactly the same problem, was playing against two friends before entrenchment nothing wrong. but after we all downloaded entrenchment they were able to play multiplayer but i couldn't join the game came up with an error saying the mesh files wern't the same. I uninstalled and reinstalled but still nothing.

This is a common problem when testing in-house as well. Like annatar said, you just have to delete everything beforehand to make sure you have the same files

ok, now it's getting really weid.

I DID the uninstall/ reinstall. also deleted every file and item I could find. for sure. I only made a copy of the achievements file and stored it in a more general folder and copied it back in after I had reinstalled.

the result: still the same problems. mesh files and all. and yet, after the install I could play a fairly long mp game in the weekend. my friend should conceivably not be the problem, I mean he wasn't in beta, didn't have any mod files or anything. he just installed entrenchment and his version and mine just don't get along. I'm really sad, you know, and a bit pissed too. what's the problem here?

edit: vanilla sins seems to be working just fine. it dropped me from my own game (my friend saw a msg saying the game had aleady started) but that is not really a new issue. in fact the game is running while I write this. maybe that helps somehow.

I'd email IC support at this point, to be honest Zip up your mesh folder and attach it, so they can take a look.