FlatOut Ultimate Carnage will not play music files which are contained inside of a packed .bfs file. This leads to an issue that many seem to be having when attempting to upload or re-upload mods created externally to the steam workshop as by default the mod manager included with the Steam release packs all mod data into a .bfs.

This guide will explain how to properly upload "loose" files and folders not packed as a .bfs to the Steam Workshop, and ultimately, how to create a working soundtrack mod accessible through the Steam Workshop

First Launch FlatOut Ultimate Carnage and select the launch option to launch the workshop tool/mod manager.

Press "Create mod" on the initial window.
Fill out the applicable Name, description and image



Now click on "Open Mod Directory" which will open a file explorer window to the "data" folder inside the mod directory, go back one level to the folder that is the name of your mod and you should see something like this.


In this folder right click and create a new folder, name this folder "upload_dir"



inside this folder is where you want to put a folder containing your .ogg music files






Now we are going to create our playlist files, navigate back to the root of the mod and open the data folder. inside of this folder is where you want to place your "playlist_title.bed, playlist_ingame.bed, and playlist_stunt.bed" files, this tutorial will not be covering these in great detail but a quick rundown of what the file looks like with an example


Loop = {
Count = 1,
[1] = {
File = "mods/tutorial/music/ArtOfDying_YouDontKnowMe.ogg",
Artist = "Art Of Dying",
Song = "You Don't Know Me",
StartPos = 0,
},
}


Count should equal the number of tracks in your playlist, each track should be numbered correctly in the brackets [#]
File should point to where the music files for your mod are expected to be once you upload them to the steam workshop. Once uploaded to the Steam Workshop the folder "upload_dir" will not exist in the root of the mod's folder for subscribers. In this guide's example, once uploaded to the Workshop the correct path for the song "Art Of Dying - You Don't Know Me" will be in "mods/tutorial/music/ArtOfDying_YouDontKnowMe.ogg"

Playlist files require at least 2 songs to be valid and play correctly in game.

Great! now if done correctly everything should be staged correctly to begin uploading your mod. simply select the "Pack" option on the mod manager. Once complete press "Publish Mod on the next menu" The tool will begin an upload to the Steam Workshop. When this upload is finished you will get an error for an unhandled exception in the program, this is normal as the program is coded to create a folder "upload_dir" and stage the .bfs file, modinfo.json and thumbnail when uploading to the Workshop. Afterwards the tool is supposed to move the files back to the root of the mod folder and deleted "upload_dir". The unhandled exception is because the folder "upload_dir" is not empty after uploading to the workshop and the tool is not coded to move your additional files and folders back to the main directory of the mod.

When the tool finishes and crashes, hurray! You have just properly uploaded a working Soundtrack Mod for FlatOut Ultimate Carnage. Other Steam users will be able to simply subscribe to your workshop item and enable it in their mod manager.

Some final notes for you, the mod creator. As the tool does not move the music folder/files automatically to the root of your mod folder for yourself you can do either of the following:

1. Yeet the entire mod folder you created for uploading to the workshop and subscribe to your own mod.

2. Simply remove the songs/folder from the folder "upload_dir" and place them in the root of the folder for your mod, then delete the now empty folder "upload_dir".

That should be everything you need to know to create a working Soundtrack Mod for FlatOut Ultimate Carnage for the Steam Workshop. For a more indepth explanation of actually replacing the soundtrack and editing the playlist.bed files check out this guide by user Ayaya.