Hi Noel; used that always and before, and if i remember right, i had a similar discussion around when 2015 or 2016 came around.
After some files been set right or reinstalled all was OK.

BYW, the 2019 installers work fine directed to that folder, and the benefit of symbols like ! ahead are that the folder on a harddrive partition is situated at the top; easy find.

BIAB 2018 runs fine from L:\!BIAB, sees all styles without errors copied to L:\!BIAB\Styles and or L:\!BIAB\Soloists, and sees all RTs OK etc within L:\!BIAB 2019\Realtracks etc.

One Q. Does BIAB do anything in the registry or some user folder that can influence this? Or some permission settings? -F