I have a strange problem. I have a small program which send a sign up notification mail to all user when the user sign up with the system. The user eventually gets a mail, which has url to authenticate the user. Everything is OK, the only problem is in a particular line there is an '! ' appearing. I have frantically checked for the occurrence of that '! ', but could not find any. I have copied the section of the mail and made a small program and executed the same, no '! ' appeared, that actually inspired me to think, that there might be some hidden non-printable character somewhere within the program, and I have written the program afresh (I practically typed line by line of the program to another document), named the document as the original one and executed, the same '! ' appeared again. I renamed the program to some other name and executed the same, the same '! ' re-appeared. I have tried all possible means to get rid of the same, but without any result. My mail is using amazon mail service to send mails. if someone can help with some clues, it will be utmost useful. It is more because, a user has noticed it, and posted it as a bug.