Major incident

ESET: MS Exchange Online email scanning delayed in US and EU

Affected: Europe, Africa, Asia Pacific, Japan, Americas, Oceania

Current status of ESET: Operational — live ESET status

Timeline

1. Sep 14, 2026, 19:29 UTC
   investigating
   We are currently experiencing a delay in MS Exchange Online email scanning that is estimated to 10-30 minutes. To mitigate the issue, the MailScanService was restarted on the SFC machines. We are currently waiting for the new TTL settings to take full effect and for the scanning process to return to normal operation. The root cause of the issue has not yet been identified and is currently under investigation.
2. Sep 15, 2026, 03:40 UTC
   investigating
   Scanning process had returned to normal operation. We'll monitor performance during work hours in case the issue reoccurs.
3. Sep 15, 2026, 08:06 UTC
   identified
   Scanning process had returned to normal operation.
4. Sep 15, 2026, 08:12 UTC
   monitoring
   The scanning process has returned to normal operation. We will continue to monitor performance in case the issue reoccurs.
5. Sep 15, 2026, 19:39 UTC
   investigating
   We are currently experiencing a delay in MS Exchange Online email scanning that is estimated to 10-30 minutes. EU and US regions are affected. To mitigate the issue, the MailScanService was restarted on the SFC machines. The root cause of the issue has not yet been identified and is currently under investigation.
6. Sep 16, 2026, 04:14 UTC
   identified
   US environment should not be affected anymore. Mail are processing without any delay. EU region still affected.
7. Sep 16, 2026, 09:08 UTC
   monitoring
   The service should be restored in both regions. We continue to monitor the behavior.
8. Sep 18, 2026, 08:08 UTC
   resolved
   The issue has been resolved.

Updates as published by ESET (original).