Exchange Removing XML Data in Attachments When Using OWA

I was working on a Symantec Mail Security appliance the other day that was passing a bunch of spam through. The problem should have been easy to fix; the license had expired. All that was necessary was to upload the new license file. I emailed it to myself and opened OWA from a server on the customer network to download the file. When I tried to install it, I kept getting an invalid license error. I called Symantec tech support and they regenerated the license and emailed it to me thinking the license was corrupt. That one worked fine. Hmmm…curious, I tried opening the license file I had downloaded from OWA. No surprise why it wouldn’t work, it was an empty text file. I did some testing emailing that file (unzipped) back and forth from account to account. It wasn’t a spam/AV filter problem. Turns out the problem was that I downloaded the file via OWA having sent it unzipped. With Exchange 2007 SP1 prior to update rollup 6, if a file that contains XML data is attached to a message, the XML content in files is removed when you open or save the attachment by using OWA. The license file was XML content…the one from Symantec support worked because it was zipped.

Networking XML Exchange 2007