UUEncoded attachments appear as garbled text
Some attachments appear as garbled text in your Outlook or Outlook Express. It usually begins with “begin 666″ and followed by chunk of encrypted messages in the message body.
Most email clients or webmail support UUEncoded attachments. Decoding is done automatically. Yet, for some reason, the decoding was prevented and this causes the problem.
Try to check if any of the senders or the recepients are using Unix machines, or if the email was handled by command prompt. Also, check to make sure the email clients or the web browsers used to launch the Webmail are not having problem.
Updates: After reinstalling the Outlook in sender PC, everything seems to be back to normal.