I’m going far out on a limb here; it could be related to culture specific parsing of text and numbers. Check that your code parses strings and numbers from text everywhere with CultureInfo.InvariantCulture - .NET doesn’t do that by default.
Thanks for the suggestion - I will look at that - considering the customer is the same culture as me (even lives in the same city) could it be that his Rhino install, which was working a week ago, has changed it language and is where he is seeing issues?
The culture info is taken from the Language and Region settings (I’m assuming windows here). Specifically also the number formats that are part of that. Might be barking up the wrong tree though.
Rhino doe not change language all of a sudden. And you’d notice because everything would be in that language.