the log says
00000.077 INFO : DCS/2.5.6.59625 (x86_64; EN; WORLD,A-10C_2,P47D30,WWII-ARMOUR,NEVADA_terrain)
These are the only modules in your install known to the updater. Haven't you happened to delete or edit the autoupdate.cfg file?
Most probably it is a hardware failure (CPU or memory if overclocked, or a loose cable/dying HDD/SDD).
If next attempts give you exactly the same error, then the failure happened when the file was being downloaded and now its disk copy is bad.
In this case delete the _downloads\Mods/terrains/Caucasus/Surface/Caucasus.surface5.* file and start update again. It will redownload the file (it's several GBs, sorry).
Just found this. An interesting take. Reminds me of Quake2 soundtrack a bit.
Btw, the original soundtrack is available on my Bandcamp page: https://c0ff.bandcamp.com/album/lockon-flaming-cliffs-2-original-game-soundtrack
And everywhere else: https://band.link/LockOnFC2
Thanks.
2020-10-19 04:11:47.796 INFO SOUND: Opening default audio device.
2020-10-19 04:11:47.798 INFO SOUND: Driver reports 1 channels with mask 0x4
2020-10-19 04:11:47.798 ERROR SOUND: Driver reported an invalid output configuration! Forcing stereo output.
2020-10-19 04:11:47.798 INFO SOUND: Using 2 channels at 48000 Hz
2020-10-19 04:11:47.798 INFO SOUND: Channel layout: Headphones/Stereo
2020-10-19 04:11:47.816 ERROR SOUND: Failed to Initialize IAudioClient: 0x88890008 (AUDCLNT_E_UNSUPPORTED_FORMAT)
Hmm, the driver reports it only supports 1 channel (0x04 = SPEAKER_FRONT_CENTER).
Current code assumes a buggy driver here and tries to force stereo config.
I guess the device is actually mono and thus the stereo attempt fails.
Let's check the following:
add the line to your Config/autoexec.cfg file (create an empty one if there's none):
sound.channel_mask = 4
This will force DCS to use mono output.
If this helps, I will adjust the code to accept mono devices.