Setting Parent Department to Inactive Sets Child Department to Inactive

When the Parent Department is set to Inactive, all of its Child Departments are automatically set to Inactive.

This is a standard behavior. Set back the Child Departments to active:

1. Navigate to Setup > Company > Departments
2. Click Edit on Parent Department
   
3. Check Inactive checkbox
4. Click Save
5. Check the Show Inactives checkbox
6. Uncheck Inactive checkbox of Child Departments that needs to remain active
7. Click Submit

Alternatively, you may set the Parent Department to Inactive in the Departments list page:

1. Navigate to Setup > Company > Departments
2. Check Show Inactives checkbox
3. Check Inactive checkbox of Parent Department
4. Click Submit

Observe that the Child Departments are not automatically set to Inactive.