I was migrating from Exchange 2003 to Exchange 2010. Email was configured to route through Exchange 2010 and out to the Internet if needed. If a user sent and email from the Web interface of Exchange 2003 to an outside internet recipient, the message looked like the following
䠼TML dir=ltr>䠼EAD>㰊META content="text/html; charset=unicode" http-equiv=Content-Type>㰊META name=GENERATOR content="MSHTML 8.00.6001.19328"㰾/HEAD>㰊BODY> 䐼IV㰾FONT color=#000000 size=2 face=Arial>OWA 2003 Gibberish Test㱴/FONT>⼼DIV>⼼BODY㰾/HTML>
Note the red was the actual message. If the same thing was sent to a recipient on Exchange 2010 the message appeared just fine.
The issue happened once a disclaimer was set up as a transport rule. So the disclaimer was causing the issue. Disable the transport rule, the issue goes away. Enable the rule, it comes back.
This problem occurs because Outlook Web Access for Exchange 2003 sets an e-mail message to an incorrect character set. When the message is routed by the Exchange 2007 or 2010 server that has the Disclaimer rule enabled, the e-mail message is converted to incorrect HTML tagging based on the incorrect character set. Then, the message is corrupted by the incorrect tagging.
A patch just for this issue. Once the patch was applied to all of the Exchange 2003 servers, all was well.
hope it helps