If I draw a simple cube and save it then on anew workspace draw another cube save it, then I try to join, I select the two sides I want to join them but get the message attached. What does it mean? I have tried to draw different cube type shapes and sometimes it works and sometimes the joint does not work.
Please can somebody advise.
That error is unrelated to the Combine. If the design is in the state before drawing your first cube, try doing a Compute All - I suspect that you will see the same error. The error appears only because the Combine forces a compute. So, as @davebYYPCU suggests, you need to look at your components and joints to see where the error is occurring.
