Filip, since the usual steps are all done, the next thing worth checking is Equalizer APO's own log: C:\Windows\ServiceProfiles\LocalService\AppData\Local\Temp\EqualizerAPO.log. Record a few seconds in Audacity from the mic, then look at the end of that file. Errors there usually name the cause, and posting them here would help Peter help you. For a fuller log, set the DWORD value EnableTrace to 1 under HKEY_LOCAL_MACHINE\SOFTWARE\EqualizerAPO and try again. Disclosure: I'm building Speaker, another...