Yay! Found it in registry!
In:

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\Terminal Services
there is "MaxDisconnectionTime", which was set to 7200000 (2 hours in ms). After...

What I meant was that there are no restarts/shutdowns, but only automatic logoffs 2 hours after disconnecting from the remote desktop (on the computer, which I was connected to). That's all what...

No, no, no. It's not random. It always logs me off 2 hours after disconnecting from Remote Desktop as shown in post #5. I don't know if You missed the screenshot or it doesn't show for you, but it's...

Sorry. Don't know how I missed the link...
There were no restarts/shutdowns lately. Last shutdown was made 18.07.2016 by myself, so that's not the case. Also didn't find any events that You...

So that's what I found:
94723

It logs me out after 2 hours of disconnecting from remote desktop.

There's no errors in Reliability History. In event log I've got something like:
94695

Errors here doesn't seem to be connected with the problem. I belive they're just thrown, because service is...

I'm using Windows 10 Enterprise. When I leave my computer I lock it using the windows key + L. After some time when I unlock the account I see that my account was logged off and I lost all my running...