Work center &1 is used in sequence &2 and sequence &3.

What causes this issue?

You are trying to edit a routing in the line balancing graphic. In this
routing, the same work center is used for operations from at least two
sequences. Routing such as this cannot be edited in the line balancing
graphic.

System Response

The line balancing graphic cannot be started.

How to fix this error?

Change the routing so that the work center is only used for operations
that are in the same sequence.
You can of course use several sequences in the routing. However, all
operations assigned to the same work center must also be assigned to
the same sequence.
If this restriction is adhered to, the routing can be edited in the
line hierarchy graphic.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.