The Luxembourg Commission de Surveillance du Secteur Financier has published a guide to help financial entities interpret and address error and warning messages generated by the European Supervisory Authorities (ESAs) when they run validation checks on submitted registers of information under DORA. The guide responds to a market request for more detailed explanations of the ESA messages and is based on the ESA validation checks list last updated on 28 April 2025. It focuses on the most frequently failed validation checks, describing the underlying issues and providing instructions on how to resolve them.