# AUR0007 ### **Error message** Resource key "yyyy" already registered ### **Parameters** Resource key ### Error explanation This error occurs when you try to register a resource (such as a custom element, attribute, value converter, or binding behavior) with a key that has already been registered in the container. Resource keys must be unique within a container. ### Common causes * Attempting to register the same resource more than once. * Using the same name for multiple resources of the same type. * A plugin or library is registering a resource with a name that conflicts with one in your application. ### How to fix * Use unique names for your resources (elements, attributes, value converters, binding behaviors, etc.). * Check for duplicate registrations in your code and in any plugins you are using. * If a plugin is causing the conflict, consult its documentation or consider renaming your resource. ### Debugging tips * Check the stack trace to see where the duplicate registration is occurring. * Search your codebase for all registrations of the resource key in question. * If using plugins, try disabling them one at a time to isolate the source. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.aurelia.io/developer-guides/error-messages/0001-to-0023/aur0007.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.