https://bugs.winehq.org/show_bug.cgi?id=43995
--- Comment #4 from debianxfce fin4478@hotmail.com --- Remove UplayCrashReporter.exe from the .wine/drive_c/Program Files (x86)/Ubisoft/Ubisoft Game Launcher/ directory to fix this bug. The game works fine without it. Backup your /home/xfce/Documents/Assassin's Creed IV Black Flag/Assassin4.ini file, some display setting can cause a black screen.