Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

Title: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users may have seen failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue specifically happened when using "$Select" as part of the query.

Affected users could've bypassed the issue by not using "$Select" in the queries.

Final status: We've confirmed that the deployment is complete and impact has been successfully resolved.

Scope of impact: This issue may have impacted any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender.

Start time: Thursday, August 13, 2026, at 8:14 PM UTC

End time: Thursday, September 10, 2026, at 6:30 PM UTC

Root cause: A code regression after a recent service update impacted OData $Select query, which caused failures.

Next steps:
- We're reviewing our feature update testing and validation methods to better identify the potential for impact to querying prior to deployment to prevent similar impact in the future, and to improve our pre-deployment update testing processes.

This is the final update for the event.

Title: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: We're continuing to monitor the saturation of the deployment, which we anticipate will complete by our next scheduled update, remediating the issue for all affected users.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender. This section may be updated as our investigation continues.

Start time: Thursday, August 13, 2026, at 8:14 PM UTC

Root cause: A code regression after a recent service update is impacting OData $Select query, causing failures.

Next update by: Friday, September 18, 2026, at 6:00 AM UTC

Title: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: We've completed the validation within our internal testing environment and begun initiating the fix deployment. As the deployment begins to propagate throughout the affected service environment, we anticipate that some users may experience relief from impact. Additionally, we expect that we will have acquired a complete remediation timeline by our next scheduled update.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender. This section may be updated as our investigation continues.

Start time: Thursday, August 13, 2026, at 8:14 PM UTC

Root cause: A code regression after a recent service update is impacting OData $Select query, causing failures.

Next update by: Tuesday, September 15, 2026, at 4:00 AM UTC

Title: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: We've started deploying the fix to our internal testing environment prior to releasing it to the affected environment. We expect the validations will be complete by our next scheduled update, and we'll aim to provide an updated resolution timeline.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender. This section may be updated as our investigation continues.

Start time: Thursday, August 13, 2026, at 8:14 PM UTC

Root cause: A code regression after a recent service update is impacting OData $Select query, causing failures.

Next update by: Wednesday, September 2, 2026, at 6:00 AM UTC

Title: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users may see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: Based on our analysis, we've determined that the code fix will take an extended amount of time to deploy to the affected environment. We're monitoring the progress and currently estimate that the fix will reach all affected environments by the middle of September 2026.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData in Microsoft Defender. This section may be updated as our investigation continues.

Start time: Thursday, August 13, 2026, at 8:14 PM UTC

Root cause: A code regression after a recent service update is impacting OData $Select query, causing failures.

Next update by: Thursday, August 27, 2026, at 6:00 AM UTC

Title: Users see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: We identified a code regression after a recent service update to Microsoft Defender for Office 365 that is impacting OData $Select queries. We've developed a code fix for the issue and are deploying to the affected environment to remediate the impact.

Scope of impact: This issue may impact any user querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

Start time: Thursday, August 13, 2026, at 6:41 PM UTC

Root cause: A code regression after a recent service update is impacting OData $Select query, causing failures.

Next update by: Saturday, August 22, 2026, at 5:30 AM UTC

Title: Users see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query

User impact: Users see failures when querying the Microsoft Graph Attack Simulation Training API with $Select OData query.

More info: The issue is specifically happening when using "$Select" as part of the query.

Affected users can bypass the issue by not using "$Select" in the queries.

Current status: We're investigating a potential issue with Microsoft Defender and checking for impact to your organization. We'll provide an update within 30 minutes.