DEVONthink has the annoying habit of starting up if I try to complete a bit of text in Emacs on my Mac. By default DEVONthink is bound in the "Services" menu to Apple-Slash (Command-Slash). To fix this, open up "/Applications/DEVONthink Pro.app/Contents/Info.plist" in Emacs. Do a search for "NSKeyEquivalent" until you see an entry that looks like this:

        <key>NSKeyEquivalent</key>
             <dict>
                 <key>default</key>                 
                 <string>/</string>
             </dict>
             <key>NSMenuItem</key>
             <dict>
                 <key>default</key>
                 <string>DEVONthink Pro/Lookup...</string>
             </dict>

Delete the "/" character from the "<string>/</string>" line. Once you log out and log back in, this should be fixed. Save a copy of this file before you change it, just in case you screw up.