BATTLETECH - No Audio, No Main menu Video, Saves Gone

[Harvell64]

One line summary of your issue
No Audio, No Main menu Video, Saves Gone

What platform are you running the game on?

Steam

What operating system do you use?
Windows 10
Which version of the game are you running?
1.8.1
What DLC do you have installed?
Flashpoint,
Urban Warfare,
Shadowhawk Pack,
Heavy Metal

Please explain your issue is in as much detail as possible.
I finished a mission, then when I tried to save, it was grayed out, saying that I couldn't save until my turn was completed. (I was in the Mech Lab, so..) Quit the game using the menu, game crashed, but didn't close. Now when loading the game, there is no sound, no background video on the menu screen, all of my saves are missing, AND I can't start a new game (Infinite Load).
Have you tried verifying your files?
Yes

Steps to reproduce the issue
Happens every time I run the game.

Attach DxDiag (PC), System Info log (Mac), or run sudo lshw -html > specs.html and uploaded specs.html (Linux)

Attach Output Log
Windows: \Users\YourUserName\AppData\LocalLow\Harebrained Schemes\BATTLETECH\output_log.txt
Mac OS: Users >{name} > Library > Logs > Unity > Player.log
Linux: ~/.config/unity3d/Harebrained Schemes/BATTLETECH/Player.log

If the game crashed, please attach the crash file with the time stamp closest to the crash.
Windows: [Steam library folder]\steamapps\common\BATTLETECH\DumpBox
For v.17 and beyond try here: C:\Users\[YourUserName]\AppData\LocalLow\Harebrained Schemes\BATTLETECH
OSX: Macintosh HD > Users > [username] > Library > Application Support > Steam > steamapps > common > BattleTech > DumpBox
Linux: [Steam library folder]/steamapps/common/BATTLETECH/DumpBox

If a save game was loaded at the start of the game session, upload it. Please make sure to upload the save game with the timestamp closest to when you loaded it.
Windows:
Steam: [Steam installation folder]\userdata[SteamID]\637090\remote\C0\SGS1
GOG: 'C:\Users\USER_ID\AppData\Local\GOG.com\Galaxy\Applications\50593543263669699\Storage\Shared\Files\C#\SGS#'
Vanilla:'C:\Users\USER_ID\AppData\LocalLow\Harebrained Schemes\BattleTech\C#\SGS#'
OSX:
Steam: Macintosh HD > Users > [username] > Library > Application Support > Steam > userdata > [SteamID] > 637090 > remote > C#> SGS#
GOG: Macintosh HD > Users > [username] > Library > Application Support > GOG.com > Galaxy > Applications > 50593543263669699 > Storage > Shared > Files > C# > SGS#
Vanilla: Macintosh HD > Users > [username]> Library > Application Support > unity.Harebrained Schemes.BattleTech > C# > SGG#
Linux:
Steam: /home/.steam/steam/userdata/[steamID]/637090/remote/C#/SGS#
GOG: /home/[username]/.config/unity3d/Harebrained Schemes/BATTLETECH/remote/C#/SGS#/
Vanilla: /home/[username]/.config/unity3d/Harebrained Schemes/BATTLETECH/remote/C#/SGS#/

Attach screenshot / video

 

[AndrewT]

The game thinks Steam is not running:

Steam [ERROR] [Steamworks.NET] SteamAPI_Init() failed. Refer to Valve's documentation or the comment above this line for more information.

Best to start with a Steam refresh:

- uninstall this game from Steam
- exit Steam
- manually delete everything in the Steam folder EXCEPT steam.exe and the /SteamApps/ folder
- run steam.exe to rebuild all that
- install this game again

If there's still a problem after that, we may need to do a clean reinstall of the game too.