I'm going to use the troubleshooting utility too but I wanted to post this here. I've noticed on both of our computers running 4.1 that if we restart our computers and then add a new log in item a sync to Dropbox does not occur. If I open 1Password's preferences under syncing it says a sync just occurred but checking the Dropbox folder I find that nothing has been updated and the added log in does not sync to our other devices.
To trigger an actual sync I have to disable syncing and then re-select the Dropbox folder. At that time an actual sync does occur which I can see in the Dropbox folder and our other devices pick up the added log in. As long as we don't restart the computers syncing proceeds correctly with any added items but a restart breaks it again. This is on two new retina Macbook Pros running the latest Mavericks version.
I will add a link to this post in the email with the diagnostic.
[Moderator: This was originally posted in Dropbox sync silently fails.]