/product-groups/tridion/tridion-sites/b/techweblog/posts/create-custom-errors-in-gui-from-event-systemIntroduction It's possible to create a custom error message in the GUI from the event system. You can use this functionality for example in the OnComponentSavePre Event (e.g. to check values of fields before saving a Component). 1. Adding the cod...en-USTelligent Community 12 Non-Production