I am using Dropbox 2.4.10 on OS X. I use Spotlight with an encfs-encrypted folder inside my Dropbox, which is mounted with the -o local option to get it to work on OS X 10.9 (see here). As a result, Spotlight puts a .Spotlight-V100 directory inside my encfs-encrypted folder. This directory, and all the files and directories within it, are owned by root:staff, which means Dropbox cannot synchronise them (I get an "Access denied" message from Dropbox on the Settings menu).
How can I get Dropbox not to attempt to synchronise this folder, and hence remove this message? Alternatively, is there another way to solve this (mostly cosmetic) problem? Note that the "Selective Sync" feature of Dropbox doesn't work for this problem, as the folder has never been synchronised, so doesn't appear in the list (at least, I think that's the reason).