Microsoft Exchange Online: potential memory management issue

From Microsoft:
Incident: MO907654, impacted service: Exchange Online, impacted feature: Portal, current status is: Service degradation
Published Time: 10/10/2024 9:49:28 AM
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.
Published Time: 10/10/2024 9:20:26 AM
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.

Published Time: 10/10/2024 1:31:44 PM


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.
Published Time: 10/10/2024 1:21:01 PM
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
Published Time: 10/10/2024 12:40:11 PM
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.
Published Time: 10/10/2024 12:30:15 PM
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
Published Time: 10/10/2024 11:58:08 AM
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.
Published Time: 10/10/2024 11:27:03 AM
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
Published Time: 10/10/2024 10:54:05 AM
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.
Published Time: 10/10/2024 10:28:41 AM
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

Published Time: 10/10/2024 1:31:44 PM

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.
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 3:30 PM UTC

Here is the latest update from Microsoft from Oct 10, 2024, 2:57 PM EDT:

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 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.