Symptoms:
In Web TimeSheet when you try to change a users primary or additional departments you may get the following error,

"User cannot have disabled Primary or additional departments."

Cause:
This generally occurs if this user was part of a department that was disabled later.
 
Resolution:
  • Run the User Details report with Department Full Path field enabled.
  • Verify the right department the users belongs to.
  • Enable the department under Departments section.
  • Edit the user profile and under the Advanced tab, uncheck the disabled department.
  • Click Done and Save.