Hi Duncan, We are using the following versions to work with WAT 4.0: - Wasp11.exe 11.1.0.16 - WaspEngineering3.exe 3.1.0.92 When I try to "prepare data for WAT", I got the following error: "A licenced copy of WAsP 10 or 11 is not available on the machine." We do have licences for both WAsP and and WEng. - Is this something to do with a bug due to the WEng 3.1 version? - The licences are registered under different names but same company name. Would that be the reason? Best Regards Utku