Exchange: Mail attachments are turning to winmail.dat
This is a very common issue but I just wanted to highlight the component which supposed to be changed here.
The issue is when one messaging system user is sending an attachment it is becoming winmail.dat. I recently got this issue in mail flow between IBM Lotus notes Domino to Microsoft Exchange 2010.
Here are the steps to fix it
- Login to your exchange server
- Open Exchange management Console
- Go to Organization Configuration à Hub Transport
- Select “Remote Domain” tab
- Go to the properties of the Default Domain
- Select “Message Format” tab
Now you can see the problem is “Determine by individual user setting”
Change “Exchange rich-text format” to “Never use” like the screen below
- Click Apply then ok.
- Restart Microsoft Exchange Transport server on every Hub transport server.
This should fix winmail.dat issue.
Microsoft MVP | Exchange Server