Hi Brian,

I didn't see any file or description associated with your post. Could you please provide a bit more context on the issue? This error message is usually seen during tolerancing when OpticStudio tries to compute the tolerancing criterion in your nominal system but failed.

There are many factors that could cause this error message, for example, the tolerance values selected, the tolerance criterion specified, the Sampling for computing the criterion, the compensators chosen. If you still see this issue, would it be possible for you to share the file so we can take a look? You could also open a case with us so we can move this to a private discussion. 

Best regards,

Hui