When you click
All Users' Tasks in the Recent Tasks panel of the vSphere Web Client, a warning box appears:
The All Users' Tasks view for Recent Tasks is currently disabled. To view tasks for all users, click More Tasks.
Administrators can enable All Users' Tasks for Recent Tasks in the webclient.properties file for vSphere Web Client. It is only recommended for small to medium sized inventories and a limited number of concurrent users.
Note: In vSphere 6.5, All Users' Tasks is the default mode for the Recent Tasks panel. The show.allusers.tasks flag is applicable only to the minimized mode of the Recent Tasks panel.