@Pantera is there a possibility / program to see, which of my programs actually use Unity? I know, I could google, but since you're the expert...
@Pantera well... I de-installed 3 games made with unity which I had currently installed. Tried Empyrion after every deinstall, always the same outcome. But... After de-installing the last unity game AND making updates for games I don't currently play (so I didn't see the neccessity to update them), I restarted Empyrion and it immidiately quit to the the desktop, this time with an error message (loosely translated): "The instruction in 0x00007FFEA5779594 referenced to internal memory at 0x0000000000000000. The process 'written' (yes, there was an english word in my german error message...) could not be executed in the RAM. Click 'OK' to terminate the program." So it really seems Empyrion doesn't like my 8 GB RAM... Edit: forgot that my browser was open when I tried the last start with the error message. Closed every unneeded program and started Empyrion again. This time I got to the main menu... yayyyy! Also my memory usage went up to 3.5 GB (haven't had that before) when I loaded a new game. But... It quit on me again, went to the desktop without any error message during level loading time. I'll get more RAM during next week and will try again. Let you know how it went.
Yup! Works! It was the missing RAM. Do I remember it wrong or did the loading time from game start to the menu increase a lot? It took almost 4 minutes until the game fully loaded... But now it works and I'm on it! Thanks a lot for the help, @Pantera !
Oh... thats a first... tried starting Empyrion via Steam link and empyrion.exe - now Empyrion didn't start as a program, but ended up as a "service" in my Taskmanager - 11% cpu usage and NOTHING else... no error, no game, nothing. Tried starting EACLauncher.exe directly out of the Empyrion folder - that got me into a working game... Any ideas on that?
I've never been able to reproduce this issue of extremely long load times from my SSD or HDD I do not know of a fix. Unfortunately no I actually don't own a steam link & I don't remember any reports for such a issue infact I thought valve discontinued them. I will resolve this thread as you have managed to resolve the issue form the OP.