The One Who Knocks
Member
It seems anti virus software doesn't like the exe and sees it as a trojan of some kind and removes it. Add the .exe to your exceptions in your anti virus and any other program that deals with viruses and you should be fine. There was also an update to steam for the game yesterday, so that may have sorted it out.
I've already done this unfortunately but thanks for the assistance regardless. The below is exactly what happens, with the exception that a moment after typing "what" a blackscreen appears for roughly two seconds (GifCam has not picked it up) before my status changes from "in-game" to "online" (this is how I have picked up the game time despite having never been able to launch it). DirectX is up to date, as are my drivers.
EDUT: Also, opening it directly from the folder has no effect. Also, my mistake, it appears I had misinterpretted your issue as the .exe doesn't become deleted in my case, instead it appears in the task manager for a few moments and then simply vanishes (which is what I mistook as 'deleted'. Oh and here is the Task Manager view if that would be more revealing (again, a black screen appears before it disappears which isn't captured):