ESET incident
MS Exchange Online email scanning delayed in US and EU
ESET experienced a major incident on September 14, 2026 affecting Europe, Africa, Asia Pacific, Japan and Americas, Oceania, lasting 3d 12h. The incident has been resolved; the full update timeline is below.
Affected components
Update timeline
- investigating Sep 14, 2026, 07:29 PM UTC
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.
- investigating Sep 15, 2026, 03:40 AM UTC
Scanning process had returned to normal operation. We'll monitor performance during work hours in case the issue reoccurs.
- identified Sep 15, 2026, 08:06 AM UTC
Scanning process had returned to normal operation.
- monitoring Sep 15, 2026, 08:12 AM UTC
The scanning process has returned to normal operation. We will continue to monitor performance in case the issue reoccurs.
- investigating Sep 15, 2026, 07:39 PM UTC
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.
- identified Sep 16, 2026, 04:14 AM UTC
US environment should not be affected anymore. Mail are processing without any delay. EU region still affected.
- monitoring Sep 16, 2026, 09:08 AM UTC
The service should be restored in both regions. We continue to monitor the behavior.
- resolved Sep 18, 2026, 08:08 AM UTC
The issue has been resolved.