How to determine what is causing Mac Pro to automatically log out and where to find logs of logout events? For the last week or so, I've been coming in to the office every morning to find my Mac Pro has logged itself out. 

Mac Pro Late 2013
macOS Catalina Version 10.15.3 (19D76)

I have been randomly trying to disable/uninstall things that I thought might be causing the issue but so far no luck. 

This morning, I thought that I had finally nailed it as when the screen came  up, it was just asking for the password as opposed to username and password as it has started doing since it started logging itself out. Turns out I had started working on a Microsoft Word document which I hadn't saved when I left for the day so that stopped the logout process in its tracks and I was greeted with:



All of the usual suspects are not the issue. E.g. I do NOT have 'automatically log out after x minutes' set. I do not have any energy saver settings that would log me out:



The user account settings also don't seem to have anything that would cause a logout:



In security and privacy, the "Require password after sleep or screen saver" is set to "immediately", and "Disable automatic login" is checked. 

Most frustratingly about this whole endeavor is that after searching and grepping for longer than I'd care to admin, I absolutely can NOT find logs indicating who or what is causing the logout. Console.app is not helpful; searching though /var/log/ and /private/var/log both as regular user and root (via sudo -i) for things like "log out", "logged out", "logout" along with many variations thereof have yielded no help. 

It seems like there should be a straightforward term and/or location where this info would be logged and I'm hoping I just can't figure out what it is. 

I'm also certain that this is a logout and not a sleep/wake deal because the last 3 or so mornings when it has happened, all of the applications I had opened when I left for the day are closed and gone. 

There have been no notable new software installations of note; but there was an OS update within the last week or so. Unfortunately I can not for sure be certain if this issue started immediately after running that update. 

Where can I find out what is causing my machine to log itself out sometime between when I leave around 5pm EST and when I get back in the next morning around 9am EST? There should be logs that detail this basic info shouldn't there? In addition to where I might look, what would be good search terms to use to find these types of events? Obviously "logout, login, logged-out" etc. aren't doing the job (NB: grepping for these terms with case-sensitivity off).

More screenshots of searching for logout etc not helping:



And checking for software updates leads to nothing being available:

| =&gt; softwareupdate -l
Software Update Tool

Finding available software
No new software available.


Update:  just had a logout in the middle of the day: login[6335]: DEAD_PROCESS: 6335 ttys000
In your utilities folder, in your Applications folder, you'll find the console app. You can use this app to look at the system logs. The console app, when started looks like so: 



There are several log files listed. I suggest you double-click on the system log and in the search box at top of window search for logout.