Message: There Are Unsent Attachments in Your Queue
Warning occurs when exiting a form saying there are unsent attachments.
Details
A new Outbox Queue feature was added to the bottom of each form.

When attaching multiple files at once, if you happen to close Vista or lose your connection before all items are attached, the next time you connect to Vista a warning will appear when exiting forms:

To resolve this, you will need to click on the "outbox" queue shown in the first image above to open the below window to see the items that failed to attach. From here you can either delete or resume upload of the document(s).

The Attachments Outbox Queue has the following features:
While the system is actively attaching files, an indicator appears in a status bar pane (lower right-hand corner) on the main menu and on each form.
Clicking on the indicator opens a window that displays the number of attachments remaining in the queue (yet to be attached), along with specific information for each item, such as attachment status, percent complete, and more.
Using the same window, you can pause and re-start the upload process; you can also move pending items up or down in the queue to change the order the system processes them.
As files are attached to their respective records, the attachment queue list in the window shrinks while the number of attachments in the respective form's Attachment Lister grows.
Steps
If the above instructions do not resolve the issue, please log a case for Viewpoint Support. For on-premise customers, we will likely need to get on the user's computer to resolve.