I have a user who is receiving the error, "The Operation Failed" when sending emails to external contacts. I can fixed the problem by going to File -> Options -> Mail and click on the "Empty Auto-Complete List". I believe it's something with the email address format. When she copy\paste an email address on to a new email and tries to email it, she gets the error. If I empty auto-complete list again and types in the email address she is able to send emails without any error. I can copy\paste the email address to a notepad and then copy\paste the email address to a new email and works perfectly. Has anyone encounter the problem with copy\paste an email address and get the error, "The Operation Failed". Thanks.