Now I see what is wrong but not how to fix it. I've got this python product that uses ZPTs and METAL. When I first visit index_html I get a cryptic error message saying something about the METAL definition. The template that holds the METAL macro is called StandardLook and is defined like this: PTF = PageTemplateFile StandardLook = PTF('zpt/StandardLook', globals(), __name__='StandardLook') index_html = PTF('zpt/index_html', globals()) If I then visit StandardLook it works; and thirdly I go to index_html again and it works. From then on it works fine. After I refresh the product the same problem occurs again. Again.... 1. I refresh the product --> no error 2. http://localhost/myinstance/index_html --> Error!! 3. http://localhost/myinstance/StandardLook --> no error 4. http://localhost/myinstance/index_html --> no error It's obvious that the StandardLook instance needs to be rendered once so that Zope can remember that that is the macro template. How do I solve this? What needs to be done? Cheers, Peter