You might open Fargo and find that it doesn't load as you expect. You don't see any of the icons that should be on the left side of the page, you don't see the T-Rex or any of the items on the right side of the page, if you have one, your menubar.opml items don't appear, and you don't see your name where the account settings drop-down menu is located.
Here is a link to a screenshot of what I described above.
Close the tab or browser window in which you opened Fargo
Log on to your Dropbox account
Click Apps, smallPicture, #prefs
Right-click tabs.json and select Delete
Open Fargo in a new tab or browser window
Fargo will load as expected, but you will not have any open tabs. At this point you can select File, Open to open any outline you have been working on and edit it as you expect.
Have at least one tab with one of your outlines
Open an outline using either File, Open by name, or File, Open by URL
Exit Fargo by closing the tab or browser window in which it is loaded
Open Fargo in a new tab or browser window
So far, every time I follow the steps above using either Chrome or Internet Explorer, I see the loading problem as described above. The problem appears to be triggered by keeping an external outline open when exiting Fargo. If you close an external outline before exiting Fargo the problem does not occur.
I have had another occurrence of the left and right icons / elements not loading, as I describe here. It seems to occur if I keep a named outline that is not one of my outlines, in this case it was Andy DeSoto's, open and exit out of the browser. The next time I open Fargo the issue appears and is resolved by deleting tabs.json.