There seems to be quite a handful of people having this issue here whereby your steam crashes along side with your rust. Hopefully you clicked on this thread or somehow managed to googled your way through here and found out that I’ve got the solution for you.
Basically there seems to be a compatibility issue here with windows 8.1
So for those who have got windows 8.1 installed you will have this problem and the only way you can get around this is by reformatting and not updating to win 8.1
Developers, I hope you will look into this as security patches for win 8 will cease during the end of June and hopefully Rust would have a new patch to fix this problem by then.
If you are not using win8.1 and are still having this problem, sorry mate, I wish you luck.