File Protection Desktop and Server employ a series of failsafes to ensure that files are successfully backed up. When the service tries to "pull" a file for backup and fails because the file is open or otherwise unavailable, it waits for the file to become available. After a few attempts, the file goes into “push” mode, which means that the File Protection service will no longer request the file; the agent will send the file as soon as it is able to access it.
With the changes in this release, when a file is busy and cannot be "pulled" by the service, the device will continue to show in a Pending backup status but will show a sub-status indicating how many files are not backing up successfully, thus allowing you to troubleshoot.
Clicking on the device, to view the Device Detail page, lists the files in question and provides you with the ability to exclude the file(s) from backup or to allow the service to continue trying to back up.
For more information about the backup process, please refer to How Backups Work.