💡 Our Technical Review in summary
1. Summary
A code regression in Exchange Online prevented contacts that were hidden from the Global Address List (GAL) from appearing in Outlook on the web people search results. While these contacts were intentionally hidden from the broad directory, the regression incorrectly suppressed them from appearing in direct user searches within the web interface.
2. Impact
Users attempting to find specific contacts via the search function in Outlook on the web may have received no results if those contacts had the “Hide from GAL” attribute enabled. This issue was limited to the web client and did not affect other Outlook platforms or the underlying contact data.
3. Status
Service Restored. The issue has been remediated following the successful deployment of a fix to the affected infrastructure. The incident lasted from December 18, 2025, to February 9, 2026. Microsoft has confirmed that the fix is fully saturated and service health is restored. Update procedures are being reviewed to prevent similar regressions in future development cycles.
Microsoft Official Issue Details
User Impact
Users’ contacts hidden from the Global Address List (GAL) did not appear in Outlook on the web people search results.
Status: serviceRestored
Service: Exchange Online
Classification: advisory
Origin: microsoft
Updates
- 2026-02-10 13:55
Title: Users’ contacts hidden from the Global Address List (GAL) did not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) did not appear in Outlook on the web people search results.
Final status: We’ve determined that a code change inadvertently caused a regression, which caused impact to occur. We’ve confirmed that the fix deployment has successfully completed and that impact has been remediated.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may have been impacted.
Start time: Thursday, December 18, 2025, at 7:52 PM UTC
End time: Monday, February 9, 2026, at 1:00 PM UTC
Root cause: A code change inadvertently caused a regression, which caused impact to occur.
Next steps:
– We’re reviewing our update procedures to better identify similar issues during our development and testing cycles.This is the final update for the event.
- 2026-02-06 13:38
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: We’re continuing to monitor the progress of the fix deployment, and expect to have an estimated time of completion by our next scheduled update.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Tuesday, February 10, 2026, at 2:00 PM UTC
- 2026-02-04 14:46
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: We’re proceeding to monitor the deployment of this fix so that we can validate its effectiveness upon completion.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Friday, February 6, 2026, at 2:00 PM UTC
- 2026-02-03 18:27
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: The fix has currently saturated to 35 percent of the affected environment. We’ll continue to monitor the deployment of this fix so that we can validate its effectiveness upon completion.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Wednesday, February 4, 2026, at 4:00 PM UTC
- 2026-02-02 21:29
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: We’ve initiated the deployment of the fix, which is progressing though saturation is slower than anticipated. We’ll provide an estimate for when the fix deployment is expected to complete when this is available.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Tuesday, February 3, 2026, at 8:00 PM UTC
- 2026-02-02 15:34
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: We’ve identified a potential cause of impact and are actively developing and validating a fix. The fix will be deployed to the affected infrastructure to validate our hypothesis and restore service health.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Monday, February 2, 2026, at 9:30 PM UTC
- 2026-02-02 14:07
Title: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search resultsUser impact: Users’ contacts hidden from the Global Address List (GAL) may not appear in Outlook on the web people search results.
Current status: We’re reviewing service monitoring telemetry to isolate the source of the issue and establish a fix.
Scope of impact: Some users attempting to retrieve contacts in Outlook on the web people search results may be impacted.
Next update by: Monday, February 2, 2026, at 4:00 PM UTC
