Hi Peter That sounds like you have independently installed Seaside and Magritte. You might miss the part connecting them together. Seaside can be used without Magritte, and Magritte without Seaside. That happens if you just install stable Seaside and stable Magritte from the configuration browser. Can you check if you have Magritte-Seaside loaded? That is in the Seaside group of Magritte. If not, you need the other option in the configuration browser, just loading the configuration of Magritte3. Then in a workspace, do-it (ConfigurationOfMagritte3 project version: #stable) load: 'Seaside'. A faster way to start can be to use one of the images from https://ci.inria.fr/pharo-contribution/ Pier, QCMagritte and Forum all come with both Magritte and Seaside preloaded. Stephan