Hi,

 

I Installed Exchange 2013 SP1 and some users were having pop account configured in their outlook 2010 client, the pop accounts are configured to put new mails in their exchange mailbox. Since Exchange upgrade mail received from pop account cannot be replied or forwarded because it is appearing as unsent mail, it is exactly the same problem encountered by multiple users with office 365:

 

http://answers.microsoft.com/en-us/office/forum/office_2013_release-outlook/office-365-outlook-2013-pop3-emails-recieved/9432c4a9-9df3-43c1-9d1d-bb9f0dac1126

 

Today I upgraded to CU6 and the problem is still there...

 I already re-created the outlook profile and outlook 2010 is sp2 and fully patched

before the upgrade, the server used was exchange 2007 and everything was ok

Can somebody help me ?

Yeah, don't do that.  Have the mail delivered to Exchange via SMTP.  Outlook doesn't serve two masters well.