troubleshooting Question

O365 mailbox users receive Winmail.dat file from on-prem users in Hybrid setup

Avatar of Tech Man
Tech ManFlag for United States of America asked on
ExchangeOutlookMicrosoft 365
6 Comments2 Solutions219 ViewsLast Modified:
We have Hybrid environment configured a few weeks ago. Started migrating users from on-Prem to O365.
Everything was working ok for the last two weeks. This morning cloud (O365) users started complaining that they receive Winmail.dat file attachments from On-premises users. Nothing that we changed on our end.  When on-prem users send email to O365 user, winmail.dat file is getting attached. Our users have formatted signature in the body of the email.
According to some articles, the recommendation is to set MailFlow\RemoteDomains\Default\Use Rich text format to NEVER.
After making this change and waiting for a couple of hours basically nothing changed.
Any thoughts?
SOLUTION
Join our community to see this answer!
Unlock 2 Answers and 6 Comments.
Start Free Trial
Learn from the best

Network and collaborate with thousands of CTOs, CISOs, and IT Pros rooting for you and your success.

Andrew Hancock - VMware vExpert
See if this solution works for you by signing up for a 7 day free trial.
Unlock 2 Answers and 6 Comments.
Try for 7 days

”The time we save is the biggest benefit of E-E to our team. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange.

-Mike Kapnisakis, Warner Bros