So, at long last I've actually got an optimisation study working, and rather well.
Having so far been optimising for displacement with a mass limit, I'm now trying to introduce some stress limits too. Unfortunately I'm getting the error above.
It's a simple static analysis that's linked to the optimisation, on a single part. There's only one static analysis defined, and one optimisation study. The measures give results when running the static analysis on its own.
What on earth is this about?
I found one single occurrence of this error message in our database. Investigation in R&D showed that it was due to a model corruption.
To fix the model, remove the design limit row that causes the failure and reinserting the limit.
I updated and published the related article now, so that it is visible in our database: CS131644
If you have the chance to verify, whether it helps in your case, too, please give me a feedback - it's always good to know whether a published article actually is of value.
Thanks Gunter. Unfortunately I've moved on from that model now so I don't have like-for-like to verify, but I'll remember this in case it happens again!