# In Flex Builder 3: Project → Clean → Clean all projects
Because Adobe’s old Flex 3 patch server ( http://fpdownload.adobe.com ) redirects to HTTPS with a modern certificate, older Java runtimes fail. Solution: Manually override the patch URL. patch listing error flex 3
file (backup it up first!) and relaunching the app to force a fresh sync. Final Thoughts # In Flex Builder 3: Project → Clean