Hi Noel, thank you for answering quickly.

It's version 2018 (520).

Song Picker worked without problem in the 2016 and 2018 versions.
I use it regularly to generate comping tracks for sax and guitar.
I noticed this strange behavior after Win 10 1809 (November) update.

I should say Song Picker rebuilds without problem. I can load files individually without problem.
I can get around the issue avoiding Song Picker.
But it's strange that I should be the only one with this problem.

I tried rebuilding on the BB demos folder (presumably sane). It rebuilt instantly and immediately froze.