Excel (and Outlook) activities should have a timeout to prevent the robot being stuck on an unexpected popup when saving or opening a workbook. We’ve noticed that there is a chance that some company wide update may revert application settings to a state where opening a workbook with links will result in a popup. Sometimes a popup makes the robot wait until it the job is terminated or someone manually logs on to the computer to manually bypass the dialog.
The popups are typically asking the user about updating the links in the workbook or in Outlook asking the user about allowing the robot to use outlook.
Similar thing happens rarely when opening or saving a workbook over the network. A progress bar is shown and only thing you can do is click Cancel, but obviously robot can do nothing to it as it is just waiting for the activity to reach a timeout of eternity.