Mac Pro (Mid 2012) 3.2 GHz Quad-Core Intel Xeon 32 GB DDR3 OS X 10.10.4 Recently (maybe 3-4 times in the last moth or so), this mac has been killing all apps and processes and booting me out to the log in screen. It is not set to ask for password on log in or after sleep or anything like that. it has also happened while I was in the middle of using the machine and killed some of my data transfers, etc. I read up on it a couple of weeks ago, and it seems to be a common issue with the graphics and the way they interact with multiple monitors or something of the sort. My issue is that this computer actually doesn't have a monitor hooked up. I use this computer for background tasks and screenshare to it to do what I need to do. My suspicion is that it has something to do with the network interface. I have multiple NAS and SAN volumes mounted at various times, and when this occurs, all of those network mounts are gone when i return to the desktop. The console diagnostic log (attached to this post) that comes up is for a WindowServer crash. NOTE: I tried attaching the diagnostic report as the .crash file, but the interface told me it was not an acceptable extension and so I saved it as .txt. Does anyone happen to have any insight as to what may be causing this? Any help is greatly appreciated.