Plugin erroneously reported as not found

We are getting the following on some clients:

SystemNotInitializedException: FMOD Studio initialization failed : Loading plugin ‘fmod_gain’ from ‘C:/Program Files (x86)/Steam/steamapps/common/…/Plugins/fmod_gain.dll’ : ERR_FILE_NOTFOUND : File not found.

However the fmod_gain.dll does exist in the reported folder, so something else must be wrong. It occurs on windows 7, 8 and 10, but only for some clients.

We are using FMOD studio 1.09.06

Have you included both the 32 and 64 bit versions of the plugin with the game?
If you try to use the wrong one, you will get ERR_FILE_NOTFOUND. To confirm you have the correct ones, you can build them as part of the FMOD Studio API.

There is only one version of the fmod_gain plugin, but whether it is compiled for 32 or 64 bit I have no idea, its the one included with the standard installation of FMOD Studio.

There are however two very similarly named fmod_studio libraries, fmodstudio.dll and fmodstudiol.dll both listed as having original filename fmodstudio64.dll.

I am not sure what building the FMOD Studio API entails, we are simply using the binaries that come with the install plus the Unity package.

It will be the same version as the FMOD Studio you installed. You can either download the other version and get the plugin from that, or download the FMOD Studio API and build the plugin yourself.

fmodstudio.dll is used for release builds and fmodstudiol.dll is used for debugging.