Did anyone check this out from in the manual: Fix "Sour" Notes ?
It says it's suppose to process MIDI.
Maybe it only works if there's audio on the track ?

I posted the Reaper snap midi scripts because I wanted to do this in Biab but couldn't so I made the scripts. If users can't do something in Biab I try to make a Reaper or Autohotkey script to do it, and say here you can try this.
I can't hack into Biab to get it to snap midi notes.

I posted about issues I used to have but the post got deleted.
I said Biab is working really well now.
I said I used to have problems with RealBand crashing, I did BUT since it was made to 64 bit I have had no crashing and I was one of those saying to go 64bit.
I said I found Reaper and it's great, I have made so many scripts to work with Biab and BBPlugin for uses with Reaper.
From using Reaper I have found ways to improve Biab & BBPlugin.
I spend so much time on this over the years to make them better, I'm not out to destroy it and run it into the ground. Look where Biab is now, it's so much better isn't it ?
I tell the truth to make things better, I can't be expected to just give sales spin and say it's all wonderful with no issues at all.
I go off at times because of frustration with it that doesn't need to be.

https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)
Open SGU in Reaper Instantly