This error happens when you are in case:

  • Site 1 has MOM
  • Site 2: create Alternate method from MOM but you don’t assign Scheduling Resource for all operations, include Subassembly operations.
  • When you get MOM on Site 2, Subassembly will display as a Material only, but the system still record operation for it (don’t display on screen).

SOLUTION:

  • Add a new SubAssembly (any part).
  • Save
  • And Delete it.

Another case is you don’t have resource on the operation. Solution is go to Operation, right click to add Scheduling Resources.