There's a knossos log in %appdata%\knossos\log.txt
Try pasting that either here or in #knossos on Discord
INFO:MainThread:launcher.main: Running Knossos 0.13.3 on PyQt5 and Python 3.6.6 (v3.6.6:4cf1f54eb7, Jun 27 2018, 02:47:15) [MSC v.1900 32 bit (Intel)].
INFO:MainThread:launcher.main: OpenSSL version: OpenSSL 1.0.2o 27 Mar 2018
INFO:MainThread:integration.init: Activating Windows integration...
INFO:MainThread:runner.run_mod_ex: Starting mod "Wings of Dawn" with cmdline "['-3dshockwave', '-soft_particles', '-post_process', '-fb_thrusters', '-fb_explosions', '-targetinfo', '-3dwarp', '-no_emissive_light', '-rearm_timer', '-ship_choice_3d', '-enable_shadows', '-stretch_menu', '-fxaa', '-dualscanlines', '-ballistic_gauge', '-warp_flash', '-snd_preload', '-ambient_factor', '50', '-spec_exp', '11', '-spec_point', '1.2', '-spec_static', '1.2', '-spec_tube', '2.0', '-ogl_spec', '60', '-bloom_intensity', '35', '-fov', '0.55', '-mod', 'wod-2.0.0-2', '-parse_cmdline_only']" and tool "C:\Games\FreespaceOpen\bin\fso-wod-17.0.0\Fs2_open_Wings_of_Dawn-EX17-SSE2.exe".
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20180725 (FSO)> is empty, ignoring it!
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20180924 (FSO)> is empty, ignoring it!
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20181111 (FSO)> is empty, ignoring it!
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20181113 (FSO)> is empty, ignoring it!
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20181114 (FSO)> is empty, ignoring it!
WARNING:Thread-5:repo.add_mod: Mod <Mod "FSO" 3.8.1-20181218 (FSO)> is empty, ignoring it!
Also; is your "Engine Preferred Stability" (Settings->Knossos) still set to "Nightlies"?
It was. I also tried setting it to Stable and RCS but that just removed the Nightlies from the list. When I try to launch the nightlies (or WoDs version) it just says "FSO is launching" and then does nothing.
Lastly, I presume the 68 day old log is your FSO log? What place on your disk did you get that log from?
I'm not sure where its pulling that from. When I selected "upload debug log" to see what it would do it said the last log was from 68 days ago.