KnowBe4 incident

Defend | Emails Not Being Rendered in Classic Outlook

Notice Resolved View vendor source →

KnowBe4 experienced a notice incident on September 11, 2026, lasting —. The incident has been resolved; the full update timeline is below.

Started
Sep 11, 2026, 12:43 PM UTC
Resolved
Sep 08, 2026, 07:00 AM UTC
Duration
—
Detected by Pingoru
Sep 11, 2026, 12:43 PM UTC

Update timeline

  1. resolved Sep 11, 2026, 12:43 PM UTC

    On Septermber 8th we made aware that inbound HTML emails rendered partially or blank in Classic Outlook due to a routine HTML library upgrade in Defend's harmful-code-removal engine interacting with Classic Outlook's legacy Word rendering engine. New Outlook and Outlook on the web were unaffected. This was strictly a display issue: no email was delayed, lost, or compromised, and threat detection remained fully active. Engineering has reverted the update to restore normal rendering. If you temporarily disabled harmful-code removal during this window, please re-enable it to ensure complete protection.