The 2019 version of BIAB does in fact render the wav file to your BB folder - specifically, J:\bb\Data\temp_wav_render.wav in your case. There is no way to change this, however there is a workaround:

Using the Drag and Drop station in the upper left of the window will render directly to your DragDrop folder, which can be set to wherever you like. Give this a shot and see if it helps, and post back here with an update. Please see the manual page here: https://www.pgmusic.com/manuals/bbw2019full/chapter4.htm#_Toolbars

As well, if you're considering upgrading anyway, newer versions of BIAB render to the target folder as Peter mentioned. As you're now on a Mac, you can crossgrade to the Mac version which will let you avoid having to use a virtual machine - these can also slow things down, particularly read/write speed over your "network" drive (the VM would limit file transfer to the speed of the virtual network interface, which is likely much slower than the hard drive).

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