OT: problem with Outlook message size

[Chris Yuzik]

My apologies for the off-topic message; I'm asking here hoping that 
someone may have run into this before and might have a solution. I have 
searched the net to no avail. Sadly, I'm not aware of a message-board or 
e-discussion list where this would be on-topic. If anyone knows of one, 
please let me know.

I'm having a strange problem with Outlook on some machines but not 
others: the message size is incorrectly reported, usually by a factor of 
4x. The problem is reproduce-able and on affected machines happens on 
each and every message. If I send a 1 MB attachment with a message, the 
message comes in and is reported by Outlook as 4 MB. A 2 MB attachment 
becomes 8 MB, and so on. There are other people with virtually identical 
configurations that are not affected.

Affected email clients: MS Outlook 2003 (SP3) and MS Outlook 2007 (SP1). 
All affected machines are running WinXP Pro SP3.

I have tried disabling all Outlook plug-ins, starting Outlook in safe 
mode, creating a new profile, even running Windows in "safe mode with 
networking" and the problem persists. I have tried disabling the 
client-level anti-virus software, as well as uninstalling it and 
rebooting. I have tried using POP3 and SSL-POP3, thinking the problem 
could be caused by the firewall. I've even tried re-imaging the machine, 
without improvement.

Saving the attachment to the local machine results in the attachment 
being sized properly.

If I set up Outlook Express to download the same email message, it comes 
in as its proper size.

Forwarding the artificially larger message to an unaffected machine has 
the message come in at the appropriate size.

Accessing the mail via a webmail client show the attachments at their 
proper sizes.

Changing over to a different email client is not an option, as Outlook 
is the only allowed email client according to the company policy.

Anyone have any suggestions?

Thanks,
Chris