AllSync & AllDup

I want to find files from folder A not duplicated in folder B,
but not the reverse.
Which settings should I activate? I have activated
"Show only files without duplicates at the search result"
but I get both files from folder A not duplicated in folder B, and
files from folder B not duplicated in folder A.
Thanks

Use the remove command "Recursively remove all files in a specific folder from the search result" and select your folder B. See search result menu bar -> Remove.