When losing Internet connection, Trimble Connect for Windows goes into offline mode.

Trimble Connect for Windows can still be used offline, as all features except the project synchronization are enabled. All changes will be synchronized when Internet connection is restored. If you add files to a project while offline, you can then upload them to the server manually after recovering Internet connection.

While being offline, the login button turns into a warning symbol, to indicate that the Internet connection has been lost. The warning symbol can also be seen under project thumbnails.

When opening a project in offline mode, it is also indicated in the Trimble Connect for Windows main title bar, where it says Project Name - offline.