Hello, I have Exchange 2010 RU6, and I cannot receive email from application with "invalid" Subject. In tracking log I can see the next error "550 5.6.0 CAT.InvalidContent.Exception: InvalidCharsetException, Character set name (UNKNOWN) is invalid or not installed" The next Thread talks about this issue, but it's no solution. http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/56fc17a2-23cb-42af-9b81-1c230f37f765 It's possible configure Exchange for permit this type of Subjects? Regards,

First suggestion would be to upgrade Exchange 2010 to either SP1 RU6 or SP2 as there have been a lot of fixes in between that may resolve your issue. I have actually seen one particular RollUp Update as the fix for this issue.JAUCG

I dont believe it's the subject but the way the message is composed by the app, is it coposed with one of these chracter sets - http://technet.microsoft.com/en-us/library/aa998600.aspxSukh

Hi pvelasco, this might help: http://support.microsoft.com/kb/2536702 BR, Timo

Hello, Seems like that the header in the incoming message is not a vaild charset name. Maybe you can try the link that Timo provide to install RU4. Best Regards, Lisa

Hi pvelasco, this might help: http://support.microsoft.com/kb/2536702 BR, Timo