Anyone try to use System.Data?
 

I get an error

The type or namespace name 'Data' does not exist in the namespace 'System' (are you missing an assembly reference?)

I've tried copying the System.Data.dll to the parts/myPart folder and used the $reference directive, and it does get rid of the error. Problem is, i cant use class in there and sometimes it blue screens.

Never mind, I had this assembly referenced in another DLL, but forgot to remove my using directive.

All good.