We’re using FMOD 2.01.10 and Unity 2020.3.0.
I’ve found that we can’t build our project if we delete the unused platforms from Plugins/FMOD/lib/. Everything continues to work without issue in the Editor, but the build process immediately exits with the error:
BuildFailedException: There is an FMOD binary missing for build target StandaloneWindows64
This is despite the fact that the Windows plugin folders are still present. Additionally, per this thread, I have ensured that the folder names have not been changed. (I in fact tried with both x64 and x86_64 to be sure.)
I am fairly sure that with the previous version of FMOD we used (2.10.07, perhaps?) we didn’t have this issue, and had deleted the unused platform plugins.
I just need a few more points to clarify what could be going on here.
Can you please let me know the following:
- All files and directories underneath {projectname}\Assets\Plugins\FMOD\lib\win
- Your selected platform architecture in Unity
- Whether or not Development Build is ticked in the Build Settings
I just deleted the unused platforms again to try to repro it and answer your questions, and… everything is still working as expected.
Looks like it’s something from the Plugins/FMOD/platforms/ folder, as I hadn’t removed anything from there, and when I did the error reappeared. Previously I had deleted most of those as well (had to keep iOS even though we’re just building for Windows for now), but they’re tiny so it’s no big deal to keep them.
Edit: And I should say, thanks for getting back to me! 
Good to hear it’s working as expected now; I got a similar error by deleting the dll meta files but it sounds like that isn’t what was happening in your case. Let us know if you get any more problems, just in case there are some deeper underlying issues here.