I had a customer who had an issue where some HTML emails that were being sent to him would not display correctly. Instead of seeing the HTML email with images etc, they would see the HTML code in the email message. They were using an Exchange 2007 server and Outlook 2003 as the email client.
There was much beating the head against the wall on this one, as it would only do it on some HTML messages and not on others. In troubleshooting we went through many steps trying to find the culprit. As it turns out, Outlook has an option to force it to display all emails in Plain Text. Meaning, even if you receive and HTML email, it will force the display into Plain Text mode. To adjust this setting view the Microsoft article at http://support.microsoft.com/kb/831607.
With this customer we checked this setting, it was not set, and yet some messages would not display in HTML. On the effected emails we would check the message headers and the MIME type would still say that the message was supposed to be HTML, but outlook would not view it as such.
This customer accessed their email on the Exchange server from more than one computer. One of the computers was their home computer. After much troubleshooting we discovered that the HTML emails were being mangled when they were read on Outlook on the home computer through a VPN connection. The only way we discovered this was to read an HTML message on Outlook Web Access from the home computer and see that it displayed correctly, we then read the message on Outlook on the computer and it did not display the message correctly, go back to OWA and now the message was damaged and would not display correctly.
Turns out the user had AVG running on their home computer and had updated to version 8.0. Version 8.0 has an option to certify that it has checked messages. When AVG certifies a message it puts its stamp at the bottom of the message that says, "No virus found in this incoming message. Checked by AVG". It was when AVG would add this text to the bottom of the message that it would damage the format of the HTML message and cause the message to no longer display correctly in Outlook or OWA.
To resolve this issue, in AVG if you go to the AVG User Interface and go to Tools, Advanced Settings. On the left hand column select Email Scanner, and then un-check Certify E-Mail. This stops AVG from adding its text to the bottom of the message and causing the message to become mangled. Another alternative for fixing would be to disable AVGs scanning of incoming email, or disable the AVG add-in to Outlook. However those options would stop AVG from scanning email and possibly open the user up to the risk of opening an infected email message. By turning off the Certify E-mail AVG will still do its job, but not effect the message.
I hope this post will be helpful to some other people and save you the amount of headache and time we spent to find this simple fix. I am not sure if the issue with AVG adding its Certification message to the bottom of emails affects only Outlook and Outlook Web Access, or if it would have the same effect on other email clients as well such as Thunderbird. If anyone has an answer to that please post a comment.
This would not be a problem if html was not stuck into e-mail messages, which were designed to carry text, not html. Html in e-mail tends to get broken a lot, and sometimes break other things as well.
ReplyDeleteLeave html to web pages, like it is supposed to be, and use some well-written text, with punctuation and white space to convey your message in an e-mail!
Think about this: If e-mail didn't try to support things it was never meant to, we might have a lot less spam (or at least more easily filtered spam) and even less e-mail worm problems.
I actually use mal-formed html as sort of a filter. I set my e-mail clients to display text-only wherever I can, and certainly to send only in text. When I get an e-mail that is mostly html, with little in the way of human-readable text in it, it is usually some bit of marketing junk, and I can quickly dispose of it.
I have also never gotten an e-mail virus or worm from self-activating code, though I attribute that more to rarely using Outlook as an e-mail client than to not-displaying html when at all possible.
I am sorry if I sound grumpy about this. I just think that the vast talent that has spread the reach of the internet, and e-mail, around the world could have come up with a new way of doing things by now that would naitively support html (if that's what people really, really want), and not just glob it onto some technology never meant to handle it.
FH