Are you finding that Microsoft Word crashes when using Dropbox?
There appears to be an issue that has been introduced with v72.4.136 of Dropbox, which causes Word 2011 to crash when attempting to browse Dropbox using File > Open or File > Save dialogs.
It works perfectly normally when you use a regular Finder window to browse and open the files from Dropbox.
It may be necessary to work around saving issues by saving to desktop and then manually re-filing into Dropbox.
Long-term solution has to be upgrading to v2016 as v2011 is increasingly outdated.