> For the complete documentation index, see [llms.txt](https://docs.aurelia.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.aurelia.io/developer-guides/error-messages/0001-to-0023/aur0005.md).

# AUR0005

Invalid resolver strategy specified: yyyy

### **Error message**

Invalid resolver strategy specified: `yyyy`

### **Parameters**

strategy (string)

### Error explanation

This error occurs when the internal state of a DI Resolver has been set to an invalid strategy value. The resolver strategy determines how dependencies are resolved (e.g., singleton, transient, etc.), and setting it to an unsupported value will cause this error.

### Common causes

* Directly assigning an invalid value to a resolver's `strategy` property.
* Corrupted or unexpected state in a custom resolver implementation.
* A plugin or library modifies resolver strategies incorrectly.

### How to fix

* Avoid directly modifying the `strategy` property of resolvers unless you are certain of the valid values.
* Use the provided APIs (`@singleton`, `@transient`, etc.) to register dependencies instead of manually changing strategies.
* If you are implementing a custom resolver, ensure you only use supported strategy values.

### Debugging tips

* Check the stack trace to see where the invalid assignment occurred.
* Search your codebase for direct assignments to `resolver.strategy`.
* If using plugins, try disabling them one at a time to isolate the source.


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