I’d first check whether ServiceNow is receiving the Outlook message as an .eml attachment rather than a normal file attachment. If the original attachment has the correct name in Outlook but becomes message.eml in ServiceNow, the issue is likely happening during ServiceNow’s email ingestion.
I’d check the Inbound Email Action/Flow, along with any scripts or Business Rules that modify sys_attachment. Comparing the original Outlook email with the attachment created in ServiceNow can also help identify where the name changes.
If you need to inspect or extract the original Outlook email and its attachments before troubleshooting, a tool such as Advik Outlook PST Converter can be useful for exporting Outlook data for analysis. But if the filename changes only after ServiceNow receives the message, I’d focus on the ServiceNow inbound processing rather than changing anything in Outlook.
