Failed to init FMOD system error code 51 no sound -solved-

When POE2 doesn't boot up and you get this message: "Failed to init FMOD system error code 51" I might have the solution for you. If you get POE2 running (you have to figure out how, could be related to the sound drivers you use), go to Windows System -> Sound -> Volume Mixer and under apps change the sound driver of Path of Exile 2. Then go to POE2 settings -> sound and change the driver on device. Of course this sound a bit stupid, cause you can't boot up POE2 at all.

So I have described my specific usercase, maybe you'll get some ideas, don't forget to read the reply under this thread.

For my PC I use a Rodecaster Duo that uses virtual channels for sound. I changed the source of the sound ingame and I shouldn't have done this, cause now I can't play POE2 with sound anymore. When I disable the Rodecaster POE2 runs, but I'm not able to fix the problem. After changing the audio input to the right source, I exit POE2 and start up my Rodecaster again and POE2 gives the same failure message. Somehow I was able to run POE2 before the error message occured, while using the Rodecaster.

I've uninstalled and installed POE2 twice after the error message, but
it didn't solve it.

Too bad that POE2 doesn't have a technical support forum like POE1 does :-(

I use Windows 11 as operating system.

So I found out how to solve this problem. I start my Rodecaster with my pc. When Windows is running I shut down my Rodecaster. Then I start POE2, of course the drivers of the Rodecaster are not there. Then I run Rodecaster (POE2 also still running), go to Windows System -> Sound -> Volume Mixer and under apps change the sound driver of Path of Exile 2. Then go to POE2 settings -> sound and change the driver on device.

PROBLEM SOLVED.

Every time now I run POE2 sound is working good again, VERY HAPPY!