Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks

Title: Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks User impact: Users may have been unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks. Final status: We've completed the manual restoration of the upstream service and after a period of monitoring, we confirmed impact is remediated. Scope of impact: Users attempting to initiate Spark sessions or open and perform actions within Microsoft Fabric Notebooks may have been impacted. Start time: Friday, May 29, 2026, at 6:55 PM UTC End time: Saturday, May 30, 2026, at 12:30 AM UTC Root cause: An issue with a routine maintenance procedure on an upstream supporting service was causing it to perform at suboptimal levels, which resulted in impact. Next steps: - To help prevent similar impact in the future, we're further working with the upstream service to understand how the maintenance procedure led to impact. This is the final update for the event.

Title: Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks User impact: Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks. Current status: We've identified that additional time is needed to complete the manual restoration of the upstream service. Once that action is complete, we'll begin validating if that process has resolved the issue, or if additional actions will be needed to fully mitigate this issue. Scope of impact: Users attempting to initiate Spark sessions or open and perform actions within Microsoft Fabric Notebooks may be impacted. Start time: Friday, May 29, 2026, at 6:55 PM UTC Root cause: An issue with a routine maintenance procedure on an upstream supporting service is causing it to perform at suboptimal levels, resulting in impact. Next update by: Saturday, May 30, 2026, at 2:30 AM UTC

Title: Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks User impact: Users may be unable to initiate Spark sessions or open and perform actions in Microsoft Fabric Notebooks. Current status: We've confirmed that an issue with a routine maintenance procedure on an upstream supporting service is causing it to perform at suboptimal levels, resulting in impact to Spark sessions and Notebook operations, and we've updated the Title, User impact, and Scope of impact fields of this communication accordingly. We're manually restoring the upstream service to a healthy state and anticipate impact may be fully remediated by our next scheduled communications update, at which point we'll verify the issue is resolved through internal telemetry. Scope of impact: Users attempting to initiate Spark sessions or open and perform actions within Microsoft Fabric Notebooks may be impacted. Start time: Friday, May 29, 2026, at 6:55 PM UTC Root cause: An issue with a routine maintenance procedure on an upstream supporting service is causing it to perform at suboptimal levels, resulting in impact. Next update by: Friday, May 29, 2026, at 11:30 PM UTC

Title: Some users may experience errors when performing actions in Microsoft Fabric Notebooks User impact: Users may experience errors when performing actions in Microsoft Fabric Notebooks Current status: We've identified a supporting upstream service is performing at suboptimal levels, resulting in poor performance when completing actions in Microsoft Fabric Notebooks. We're working to identify any possible mitigation options while in parallel investigating the root cause of the upstream impact. Scope of impact: Some users may experience errors when performing actions in Microsoft Fabric Notebooks during this impacting event. Start time: Friday, May 29, 2026, at 6:55 PM UTC Next update by: Friday, May 29, 2026, at 9:30 PM UTC

Title: Some users may experience errors when performing actions in Microsoft Fabric Notebooks User impact: Users may experience errors when performing actions in Microsoft Fabric Notebooks Current status: We're investigating a potential issue with Microsoft Fabric and checking for impact to your organization. We'll provide an update within 30 minutes.