Symptoms
After you install the September 2026 Security Update for Microsoft Exchange, Exchange environments that process email messages that contain Korean language content might experience one or more of the following symptoms:
- Search results might be missing.
- Email delivery might be delayed.
- MAPI or Outlook clients might become unresponsive, stall, or disconnect.
Cause
The required assembly files for the updated Korean WordBreaker are not installed as part of the September 2026 Security Update for Microsoft Exchange.
Resolution
To fix this issue, install the following Security Update or later updates:
Note
- If you previously copied files to your servers manually by following the documented workaround, no additional action is required after installing the October 2026 update or any subsequent release.