GitHub Copilot experienced critical availability issues on June 17, 2026, between approximately 03:35 UTC and 04:44 UTC. Multiple frontier chat models became unavailable across all regions, with affected users seeing models disappear from selection interfaces or encountering "model not available" errors. The service is now fully resolved.
GitHub is a widely-used platform where developers build, collaborate on, and host code. Copilot is the company's AI-powered coding assistant, integrated into developer tools and web interfaces.
GitHub's production systems flagged a configuration change as invalid, which triggered the widespread model unavailability. The company mitigated the incident by reverting the problematic configuration. Because the outage occurred during off-peak hours, the number of affected customers was limited.
GitHub said it is implementing stronger validations for configuration changes, adding alerts for sudden drops in available models, and deploying automatic rollbacks when such alerts trigger. The incident is now fully resolved.