I recently used Migration Assistant to transfer data from my old Mac Book Pro to my new iMac 27". (sooo many pixels!) While doing so it dropped my profile into a different home directory than I had on my previous machine. Needless to say that caused a whole slew of problems. So I followed the instructions in Apple's support article on How to change your account name or home directory name.
When I rebooted after getting all that taken care of; everything else was fixed. Now Dropbox kept giving me a message and a debug dump to send to Dropbox support. As a free user they would take 1-3 business days to get back to me. I didn't have that kind of time. I ended up finding an article on fixing issues with Dropbox starting up. This gave me the ammunition I needed to nuke the installation from orbit:
$ rm -rf ~/.dropbox
Once that code has been run you can re-launch Dropbox and it will re-configure itself. You can even leave the
~/Dropbox dir in place. (assuming the permissions are all rainbows and unicorns)
PS — Of course just to post this blog I had to re-install RVM, bundle install, and shoot myself in the face.