1. In the Excel user interface
Each time when the user logs into the system, or the Excel Server service is stopping, or when a workflow task has been completed, there will be a notification message popped up in the user interface.
2. In the Web user interface
ESWeb engine will poll for the arriving of any workflow task every 1 minute. If there is a workflow task coming, a notification message will pop up.
From the “Start” menu, select “Excel Server” entry, then the “Service Manager”.

Click on the “Enable message prompt” checkbox.