A user today had a problem when they were using the Import Command - every time they ran the command TBC would lock up. The reason was that they had pathed previously to a path not accessible in their current location on Dropbox - the problem is that the Import Command remembers the last known access location for files to Import and stores it in the user.options file in your App Data folder.
The solution to the problem is to delete the user.options file and restart TBC
The full path to your App Data folder is
C:\Users<userName>\AppData\Roaming\Trimble\Trimble Business Center<TBC version>\User.options
This folder may be hidden on your computer - if it is just type in the full path using your UserName and you will find it.
Hope this helps
Alan