Some users may encounter performance issues with Outlook

Title: Some users may encounter performance issues with Outlook

User impact: Users may encounter performance issues with Outlook

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash. This issue affects all Outlook connection methods, including the desktop client and Outlook on the web.

This issue has been remediated; however, affected users will need to take action to apply the changes we’ve made to fix the problem:

- Outlook client and app users should restart their client or app to apply our changes. Outlook desktop client users may need to perform this action twice due to caching issues.

- Outlook on the web users should refresh their sessions. If that does not mitigate the issue, users are encouraged to clear their browser cache and refresh their Outlook on the web session.

Current status: Our telemetry continues to show that our mitigation actions have been effective, and we’ve entered a period of extended monitoring to ensure continued stability.
We’re continuing to coordinate with customers on reports of lingering impact that we’ve received. For those users still experiencing impact, please refer to the “More info” section of this communication for guidance on actions your users may need to take to apply our solution and fully remediate the problem.

Scope of impact: Impact is predominately to the Outlook client, though users of any connection method including Outlook on the web and Outlook mobile apps may be affected.

Preliminary root cause: A separate service-impacting event caused an issue retrieving policy data. This caused Outlook users to experience high system memory usage, which resulted in poor performance and crashes.

Next update by: Thursday, October 10, 2024, at 10:30 PM UTC

Title: Some users may encounter performance issues with Outlook

User impact: Users may encounter performance issues with Outlook

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash. This issue affects all Outlook connection methods, including the desktop client and Outlook on the web.

This issue has been remediated; however, affected users will need to take action to apply the changes we’ve made to fix the problem:

- Outlook client and app users should restart their client or app to apply our changes. Outlook desktop client users may need to perform this action twice due to caching issues.

- Outlook on the web users should refresh their sessions. If that does not mitigate the issue, users are encouraged to clear their browser cache and refresh their Outlook on the web session.

Current status: Our telemetry, testing, and coordination with affected customers continues to indicate that our fix is effective. Please refer to the “More info” section of this communication for guidance on actions your users may need to take to apply our solution and fully remediate impact.

We’re continuing to monitor our service environment and are performing tests to identify any additional actions that may be needed to ensure ongoing stability and availability.

Scope of impact: Impact is predominately to the Outlook client, though users of any connection method including Outlook on the web and Outlook mobile apps may be affected.

Preliminary root cause: A separate service-impacting event caused an issue retrieving policy data. This caused Outlook users to experience high system memory usage, which resulted in poor performance and crashes.

Next update by: Thursday, October 10, 2024, at 8:30 PM UTC

Our telemetry indicates that impact has been remediated. We’re continuing to perform tests and work with affected customers to confirm that the issue is resolved, and identify any further actions that may need to be taken.

Affected users will need to take action to apply the changes we’ve made and remediate impact:

- Outlook client and app users should restart their client or app to apply our changes. Outlook desktop client users may need to perform this action twice due to caching issues.
- Outlook on the web users should refresh their sessions. If that does not mitigate the issue, users are encouraged to clear their browser cache and refresh their Outlook on the web session.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with Outlook

User impact: Users may encounter performance issues with Outlook

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash.

Current status: We’ve applied a configuration update and our testing indicates that this action has successfully mitigated impact. However, affected users will need to take action to apply the changes we’ve made and remediate the problem:

- Outlook client and app users should restart their client or app to apply our changes. Outlook desktop client users may need to perform this action twice due to caching issues.

- Outlook on the web users should refresh their sessions. If that does not mitigate the issue, users are encouraged to clear their browser cache and refresh their Outlook on the web session.

We’re working with impacted customers and are continuing to perform tests across the affected infrastructure to confirm that impact has been successfully addressed.

Scope of impact: Impact is predominately to the Outlook client, though users of any connection method including Outlook on the web and Outlook mobile apps may be affected.

Preliminary root cause: A separate service-impacting event caused an issue retrieving policy data. This caused Outlook users to experience high system memory usage, which resulted in poor performance and crashes.

Next update by: Thursday, October 10, 2024, at 7:30 PM UTC

Our testing and telemetry indicates that our configuration update has successfully mitigated impact. However, affected users will need to take action to apply the changes we’ve made and remediate impact:

- Outlook client and app users should restart their client or app to apply our changes.

- Outlook on the web users should refresh their sessions. If that does not mitigate the issue, users are encouraged to clear their browser cache and refresh their Outlook on the web session.

This quick update is designed to give the latest information on this issue.

We’ve applied a targeted configuration update in an effort to mitigate impact. We’re conducting tests across the affected infrastructure and are monitoring service telemetry to determine if our update has had the desired effect.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with Outlook

User impact: Users may encounter performance issues with Outlook

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash.

Current status: Our investigation is presently focused on an issue affecting a separate portion of our service infrastructure as the likely cause of impact. We’re working on a potential solution and are preparing to apply a targeted configuration update that we suspect will alleviate the impact.

Scope of impact: Impact is predominately to the Outlook client, though users of any connection method including Outlook on the web and Outlook mobile apps may be affected.

Next update by: Thursday, October 10, 2024, at 6:30 PM UTC

Following further investigation, we have determined that Outlook on the web is likely not a viable workaround for most organizations affected by this issue. As a result, we have removed this guidance from our communications. We understand the impact this issue has on affected organizations and are actively working on alternative solutions while our engineering teams focus on resolving the problem.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with Outlook

User impact: Users may encounter performance issues with Outlook

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash.

Current status: We're continuing to replicate the issue internally as we work to pinpoint the source of impact. Additionally, we've identified a potential issue affecting a separate portion of our service infrastructure which may be contributing to the overall impact of this incident. We're investigating further to determine our next steps and develop a mitigation plan.

Scope of impact: Impact is predominately to the Outlook client, though users of any connection method including Outlook on the web and Outlook mobile apps may be affected.

Next update by: Thursday, October 10, 2024, at 5:30 PM UTC

We are currently reviewing memory dump logs and Outlook client telemetry data collected from affected users. We are also gathering additional information to support our analysis and help determine the next steps.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with their Outlook client

User impact: Users may encounter performance issues with their Outlook client.

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash.

Current status: Our investigation remains focused on isolating the source of a potential memory management issue which may be responsible for causing impact. We're working directly with some impacted organizations and are replicating the issue internally to generate additional data to further our efforts toward mitigation.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure.

Next update by: Thursday, October 10, 2024, at 4:30 PM UTC

We're obtaining memory dumps and logs from Outlook client telemetry data for additional analysis to determine our next steps.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with their Outlook client

User impact: Users may encounter performance issues with their Outlook client.

More info: Users may notice Outlook using an increased amount of system resources, causing the client to freeze or crash.

Current status: We're making progress analyzing a potential memory management issue which may be responsible for causing impact. In parallel, we're continuing to attempt to reproduce the issue internally and we're reviewing data provided by customers experiencing crashes and high memory utilization when using the New Outlook desktop application to develop a mitigation plan.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure.

Next update by: Thursday, October 10, 2024, at 3:30 PM UTC

We're analyzing a potential memory management issue which may be responsible for causing impact. We're reviewing additional telemetry logs further to determine if this is the root cause.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with their Outlook client

User impact: Users may encounter performance issues with their Outlook client.

More info: Users may notice Outlook using an increased amount of resource utilization, causing the client to freeze or crash.

Current status: We're continuing to analyze data provided by customers experiencing crashes and high memory utilization when using the New Outlook desktop application. Additionally, we're reviewing service telemetry and reproducing the issue internally to isolate the root cause and develop a mitigation plan.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure.

Next update by: Thursday, October 10, 2024, at 2:30 PM UTC

We're analyzing data from customer reports where they are unable to use the New Outlook desktop application due to crashes and high memory consumption.

This quick update is designed to give the latest information on this issue.

Title: Some users may encounter performance issues with their Outlook client

User impact: Users may encounter performance issues with their Outlook client.

More info: Users may notice Outlook using an increased amount of resource utilization, causing the client to freeze or crash.

Current status: We're investigating telemetry logs provided by impacted customers, as well as continuing to analyze service telemetry further to identify the root cause so that we can develop our remediation plan. We've recycled components which has reduced timeout errors, and are now analyzing diagnostics for Outlook client and Outlook on the web.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure.

Next update by: Thursday, October 10, 2024, at 1:30 PM UTC

Title: Some users in Europe may be unable to log in to Outlook and other Microsoft 365 services

User impact: Users in Europe may be unable to log in to Outlook and other Microsoft 365 services.

More info: For Outlook, affected users may experience the client crashing, be unable to receive emails and observe high memory usage in the task manager.

Current status: We're continuing our review into service telemetry and we've identified timeout errors which we're analyzing further to identify the root cause. In parallel, we're attempting to alleviate impact by recycling application pools within the affected infrastructure. Additionally, we're reviewing if other Microsoft 365 services are also impacted.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure in Europe.

Next update by: Thursday, October 10, 2024, at 1:30 PM UTC

Title: Some users in Europe may be unable to log in to Outlook and other Microsoft 365 services

User impact: Users in Europe may be unable to log in to Outlook and other Microsoft 365 services.

Current status: We're analyzing service telemetry, specifically networking data and authentication specific to the Netherlands, and further investigating potential impact to other Microsoft 365 services.

Scope of impact: Impact is specific to some users who are served through the affected infrastructure in Europe.

Next update by: Thursday, October 10, 2024, at 11:30 AM UTC

Title: Some users in the Netherlands are reporting issues with the Microsoft 365 service

User impact: Users in the Netherlands are reporting issues with the Microsoft 365 service.

Current status: We're investigating a potential issue with the Microsoft 365 service in the Netherlands. We'll provide an update within 30 minutes.