Knowledge

DNS_ERROR_CANNOT_FIND_ROOT_HINTS - 9564 (0x255C)

The DNS server could not find a set of root hints.

Updated: Feb 21, 2026

Technical Background

The DNS_ERROR_CANNOT_FIND_ROOT_HINTS error indicates that the Domain Name System (DNS) server encountered a failure while attempting to locate root hints. Root hints are critical for name resolution, as they provide initial pointers to authoritative DNS servers.

Error Details

This specific error is related to the DNS client resolver library in Windows. It occurs when the system cannot find or retrieve the necessary root hints required for initiating the DNS query process. This can lead to failure in resolving domain names to IP addresses.

Common Causes

  • Incorrect DNS Client Configuration: The DNS client may not be properly configured, leading to an inability to locate root hints.
  • Network Connectivity Issues: Poor network connectivity or issues with the DNS server infrastructure can prevent the retrieval of root hints.
  • DNS Server Outages: If the DNS servers hosting the root hints are down or experiencing issues, the resolver library will fail to find them.

Real-World Context

This error is critical for ensuring proper name resolution in networked environments. Without root hints, the DNS client cannot initiate a successful query process, leading to potential service disruptions and user frustration.

Is This Error Critical?

Yes, this error can significantly impact network functionality by preventing users from accessing internet resources or internal network services that rely on DNS for name resolution.

How to Diagnose

  1. Review DNS Client Configuration: Ensure the DNS client is correctly configured with valid and reachable DNS servers.
  2. Check Network Connectivity: Verify that the system has proper network connectivity to reach the DNS servers hosting root hints.
  3. Monitor DNS Server Status: Confirm that the DNS servers are operational and not experiencing outages or maintenance issues.

How to Resolve

  1. Correct Parameter Usage: Ensure all parameters related to DNS client configuration are set correctly, including primary and secondary DNS server addresses.
  2. Adjust Operation Context: If network conditions are poor, consider using a more reliable network connection or alternative DNS servers.
  3. Restore Data: In cases where data corruption might be an issue, restore the correct root hints from a backup source.
  4. Retry Operation with Valid Inputs: Attempt to resolve names again after addressing any identified issues.

Developer Notes

Developers should ensure that their applications handle this error gracefully and provide appropriate user feedback or retry mechanisms when encountering DNS_ERROR_CANNOT_FIND_ROOT_HINTS.

Related Errors

  • ERROR_NO_SUCH_LOGON_SERVER: Indicates an issue with the logon server, which may indirectly affect DNS resolution if the servers are co-located.
  • ERROR_INVALID_PARAMETER: May indicate incorrect parameters passed to the DNS client resolver functions.

FAQ

Q: What causes DNS_ERROR_CANNOT_FIND_ROOT_HINTS?

A: Common causes include misconfiguration of DNS clients, network connectivity issues, or outages at the DNS servers hosting root hints.

Q: How can I prevent this error from occurring?

A: Regularly update and validate your DNS client configuration, ensure stable network connections, and monitor the status of your DNS servers.

Summary

DNS_ERROR_CANNOT_FIND_ROOT_HINTS is a critical error in Windows that indicates an issue with locating root hints necessary for name resolution. Proper diagnosis and resolution involve reviewing DNS client settings, network connectivity, and server availability. Developers should handle this error robustly to ensure smooth operation of their applications.