PROBLEM
The CPU of one of the Back4 servers is normally between 80%-99% as you can see below and most of the consumption comes from back4 service.
CAUSE
The cause may be related to tasks. Some users may have no permissions to execute tasks.
SOLUTION
Change all tasks to run as administrator.
Save the TasksTable content in the file TasksTable.rpt and then I empty the TasksTable.
The CPU usage will return to normality.