1) In Zotero click on Tools menu item then select Zotfile Preferences.:
2) A pop-up window will appear (the default tab is General Settings).
Look at section on this page that says "Source folder for attaching new files"
Set "Source folder for attaching new files" for your computer’s Downloads folder:
3) Look in this same window (Tools> Zotfile Preferences> General Settings) Look at the section where it says “Location of files"
Set this to “Custom Location" and point it to the folder you created in Dropbox.
Leave "use subfolder defined by" UNCHECKED:
4) Look the tab above that says “Advanced Settings” and select it:
Check "remove special characters":
