added the folder path to avast's exception and unfortunately same problem.
fully working without any mods!
Hm, i can confirm i use abyss successfully, i hate spelling that word, on win10, with avast, with data folder, and even a few mod_sharker mods. I have a friend who says he can't get abyss to work though, without any data mods installed.
If nothing else, you may assume there's an entry in abyss itself, that is causing a conflict for you for some reason. The normal log just shows success/fail messages, it wouldn't reflect there most likely. I'm saying this based on messing around with mod_sharker, as i have issues with one of them regularly crashing me with a generic 'mabinogi has stopped responding' message. Yet the log for mod_sharker tells me that all mods are successfully loaded, and i can actually log in most the time.
My recommendation, try turning all entries in abyss to off, ie =0, and see if you can boot up. If so, then yes it's a specific entry in abyss, and it's a matter of narrowing down which one. Basically trial and error.