💡 Our Technical Review in summary
Service Health Advisory: Microsoft 365 Copilot Chat
1. Summary
IT Administrators may be unable to retrieve Microsoft 365 Copilot Chat messages when performing Microsoft Purview eDiscovery searches. This issue is caused by a latent code error that prevents message metadata from being indexed correctly, making certain messages invisible to the search engine.
2. Impact
Affected Audience: IT Admins and Compliance Officers.
Scope: Search results in Microsoft Purview eDiscovery may be incomplete. Specifically, Copilot Chat messages that should meet search criteria may not appear in the results, potentially impacting legal discovery and internal compliance investigations.
3. Status
Current State: Service Degradation / Remediation in progress.
Latest Update: Microsoft has developed a fix and successfully deployed it to a subset of affected users.
- Root Cause: A code error resulted in parsing failures, preventing metadata from being properly indexed.
- Next Steps: The final deployment to all remaining users is scheduled to begin on Monday, March 23, 2026.
- Next Update expected by: Monday, March 23, 2026, at 8:00 PM UTC.
Microsoft Official Issue Details
User Impact
Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Status: serviceDegradation
Service: Microsoft 365 Copilot Chat
Classification: advisory
Origin: microsoft
Updates
- 2026-03-20 19:21
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: We’ve developed and deployed a fix to a subset of affected users, who should start to see relief of this issue as it saturates. We intend to proceed with a meticulous deployment of this fix to the remaining affected users on Monday, March 23, 2026. We’ll provide updates to the full remediation timeline as soon as they become available.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Root cause: A latent code error is preventing some metadata from being indexed as expected, which is resulting in impact.
Next update by: Monday, March 23, 2026, at 8:00 PM UTC
- 2026-03-13 17:03
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: Our investigation has confirmed that a latent code error is preventing some metadata from being indexed as expected, resulting in impact. We’ve developed a fix and are in the process of safely releasing the change to remediate impact. We expect the fix will be fully released by the next scheduled update.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Root cause: A latent code error is preventing some metadata from being indexed as expected, which is resulting in impact.
Next update by: Friday, March 20, 2026, at 9:00 PM UTC
- 2026-03-10 16:54
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: We’re progressing with our analysis into the isolated parsing failures as we determine the source for this event. In parallel, we’re further reviewing an internal setting adjustment to determine if it may be viable for addressing the eDiscovery search problems admins are experiencing when searching for some Copilot Chat.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Next update by: Friday, March 13, 2026, at 5:30 PM UTC
- 2026-03-09 19:05
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: After using the data generated by our reproduction to review the indexing model, we’ve found that some necessary data from the Copilot Chat messages isn’t being parsed, resulting in some messages being unavailable during the search. We’re continuing to investigate these parsing failures to isolate their source and determine our next troubleshooting steps.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Next update by: Tuesday, March 10, 2026, at 5:30 PM UTC
- 2026-03-06 20:37
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: We’re using data generated by our reproduction of the impact through our internal testing environment to investigate the indexing model for the conversation history in the portion of storage infrastructure responsible for storing Copilot Chat messages, which will help us pinpoint the source of the indexing issue.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Next update by: Monday, March 9, 2026, at 8:00 PM UTC
- 2026-03-06 18:52
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: Our initial review of the Copilot Chat messages that aren’t appearing in the eDiscovery searches suggest that their indexes aren’t matching the associated keywords. We’re using our internal testing environment to troubleshoot and gain further understanding on what issue is occurring with the indexes.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Next update by: Friday, March 6, 2026, at 9:30 PM UTC
- 2026-03-06 17:04
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: We’re reviewing the explanation of the scenario provided by a subset of impacted users so that we can gain clarity on the issue and determine the next steps to isolate the root cause.
Scope of impact: Admins performing eDiscovery searches that should contain Copilot Chat messages may be impacted by this event.
Next update by: Friday, March 6, 2026, at 6:30 PM UTC
- 2026-03-06 16:40
Title: Admins may not be able to search for Microsoft 365 Copilot Chat messages using Microsoft Purview eDiscovery searchesUser impact: Admins may not be able to search for Copilot Chat messages using eDiscovery searches.
Current status: We’re investigating a potential issue impacting Microsoft 365 Copilot Chat and checking for impact. We’ll provide an update within 30 minutes.
