Regression in windows runners for public repositories

Resolved

On Jan 26, 2026, from approximately 14:03 UTC to 23:42 UTC, GitHub Actions experienced job failures on some Windows standard hosted runners. This was caused by a configuration difference in a new Windows runner type that caused the expected D: drive to be missing. About 2.5% of all Windows standard runners jobs were impacted. Re-run of failed workflows had a high chance of succeeding given the limited rollout of the change.The job failures were mitigated by rolling back the affected configuration and removing the provisioned runners that had this configuration. To reduce the chance of recurrence, we are expanding runner telemetry and improving validation of runner configuration changes. We are also evaluating options to accelerate the mitigation time of any similar future events.

Investigating

At 23:45 UTC we applied a mitigation to take remaining impacted capacity offline and are seeing improvement. We will update again once we've confirmed the issue is resolved.

Investigating

Our investigation into GitHub Actions 4 Core Windows runner failures in public repositories is ongoing.If you have a failing GitHub Actions run, please retry it and it is likely to succeed.

Investigating

We're continuing to investigate failures in GitHub Actions 4 Core Windows runners in public repositories. If you have a failing GitHub Actions run, please retry it and it is likely to succeed.

Investigating

Rollback has been completed, but we are still seeing failures on about 11% of GitHub Actions runs on 4 Core Windows runners in public repositories.If your workflow fails to start, try re-running and it is likely to work a second time.

Investigating

Mitigation for failing GitHub Actions jobs on 4-Core Windows runners is still being mitigated. You should start to see more runs succeeding.If you do see failing runs, please retry and they might succeed.

Investigating

We've applied a mitigation to unblock running Actions. A regression occurred for Windows runners in public repositories which caused Actions workflows to fail. A mitigation is in place and customers should expect to see resolution soon.If you have a failing Actions workflow on a Windows runner, please retry and it is likely to work.

Investigating

We are investigating reports of impacted performance for some GitHub services.