I'm having problems using the vst~ object with an Audio Unit. It's very possible the error is in my AU code, but I've been through it several times and wanted to check if there are any known issues with vst~, before I dive in to debugging once again.

The AU takes n input channels and m output channels, where n < m. If I configure vst~ to have n inlets and m outlets, the first n channels of output are fine, the remainder appear to duplicate each other. (I suspect that output channel n+1 is what's being duplicated, but the way the AU works makes it rather hard to say.)

If I configure the vst~ object as m in, m out (but only connect n inlets), it seems to work fine.

The AU takes n input channels and m output channels, where n < m. If I configure vst~ to have n inlets and m outlets, the first n channels of output are fine, the remainder appear to duplicate each other. (I suspect that output channel n+1 is what's being duplicated, but the way the AU works makes it rather hard to say.) 

vst-object-in-max-6

If you have an AU which shows weirdness in Max 6 but seems to work right in other hosts, please feel free to send it in to support.

vst~ object in Max 6