Hi, Just to let you know that I have started implementing error handling in the new rendering. Right now my idea is to wrap macro errors (macro not found, macro execution error) in an ErrorBlock so that renderers can decide to display them as they want. Something like the following (note: I think I need to add another <!-- errordescription:(description)--> comment for putting error description (like the staktrace) in addition to the short error message. .#----------------------------------------------------- .input|xwiki/2.0 .# Verify behavior when macro doesn't exist .#----------------------------------------------------- Unknown {{unknown/}} macro .#----------------------------------------------------- .expect|event .#----------------------------------------------------- beginDocument beginParagraph onWord [Unknown] onSpace beginError: [Unknown macro: unknown] onMacroInline [unknown] [] [] endError: [Unknown macro: unknown] onSpace onWord [macro] endParagraph endDocument .#----------------------------------------------------- .expect|xhtml .#----------------------------------------------------- <p>Unknown <!--starterror:Unknown macro: unknown--><!-- startmacro:unknown|-||-|--><!--stopmacro--><!--stoperror--> macro</p> .#----------------------------------------------------- .expect|xwiki .#----------------------------------------------------- Unknown {{unknown/}} macro .#----------------------------------------------------- .input|xhtml/1.0 .#----------------------------------------------------- <html><p>Unknown <!--starterror:Unknown macro: unknown--><!-- startmacro:unknown|-||-|--><!--stopmacro--><!--stoperror--> macro</p></ html> I still haven't decided if MacroTransformation should still raise exceptions or not. I'm also investigating how to handle other rendering errors but my idea is also to wrap them in error blocks. Let me know what you think and respond quickly if you don't agree with this since I'm progressing fast on it. Thanks -Vincent