Andy, very good question. However I would question the answer as regards the number of sub directories as the MSDN article quotes that restriction as Nesting Level restriction, not a restriction on subdirectories per sa:

"You cannot store more than 15 levels of subdirectories in the FileTable directory. When you store 15 levels of subdirectories, then the lowest level cannot contain files, since these files would represent an additional level"

Of course I may completely have misunderstood or misinterpreted, in which case I look forward to being enlightened :blush:.