I am working on a complex assembly containing a number of similar parts. I have one "master" part to which the geometry of all of the other parts is related within the assembly (i.e. I brought the parts in under-defined and created relations to the "master"). After creating a number of these parts I made a small change to the "master" part and found that many of the relations I had previously created had been broken, leaving the parts under-defined.
Can anyone suggest a way to fix this, or alternatively, another way of approaching the assembly setup?
It's hard to say without actually looking at the model, but I suspect that your "small" change to the master part ended up deleting or changing the identifiers for some of the items you were mating to. It is safest to use planes and axes for mating that are defined off of the default planes and a minimum number of sketches.