if you have already uninstalled, go to your Macintosh HD > Library > AUDIO > Plug-Ins > HAL and here you will find the driver of the program please remove the voxal folder and restart your Mac. Test again, if that does not work do the same but this time follow this path:
Macintosh HD > Library > Application Support > VOXAL > delete the VOXAL folder and restart your computer and test again.
If you still have issues you might want to contact NCH Tech Team here: https://www.nch.com.au/support/index.html