[Startup Bug]

It's like video recording software, but it allows your computer to share it's monitors contents across a network live so you can either broadcast what you're doing, or someone else can assist by logging into your computer from another computer. If you're not familiar with it and don't use a shared computer, then you won't have it.

Okay, Steam isn't what you just described, thanks! Also good news, I don't know exactly why, and I don't believe there was an update when I launched warframe; but at any rate, it worked for me this time. 

[Startup Bug]

This happens to me if I'm running TeamViewer. Make sure you're not running a video conferencing or remote login program. Warframe doesn't like those.

 Not entirely sure what you mean by "video conferencing or remote login program." However, would Steam be considered one of these? - Because I am having the exact same problem as fableeclipse.

[Montes, Venus Archwing Bug]

I also just got this problem, the mission was working fine before the most recent update, but now it isn't. After a short period of time in that part of the mission, my client froze and the computer told me something had stopped working in the client and I was forced to close the client.