I said above that my problems went away after stopping and starting Dropbox, but also after manually finding a conflicted file (ie a file where Dropbox cannot tell which of two versions of that file are correct, so keeps both, but renames one with 'conflict' in its name and added date & time details). Why a conflicted file got created in the first place is a mystery to me, but maybe I edited the file at just the wrong moment as teh dropbox client updated to the latest software version.
The way to find these, if you use Windows, is to open a command window (google for that for your version of Windows if you don't know how to) and then search for files with 'conflict' in their name. I use the command:
dir /b /s "C:\Dropbox\*conflict*"
The asterisks and the double-quote characters are required.
I issue this command every day automatically and can tell if the search works because I have a few innocent test files scattered through my dropbox with 'conflict' in their names... and those should always be found. And, for example, a file that is part of LibreOffice also does, so I always see
C:\Dropbox\PortableApps\PortableApps\LibreOfficePortable\App\libreoffice\share\config\soffice.cfg\modules\scalc\ui\conflictsdialog.ui
as one of the results.
