# 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.