Receiving blank emails when trying to encrypt emails
We are facing the following scenario:
We have a Universal server setup with 3 clients running PGP Desktop.
When encrypted emails are sent from Win7 machines, Win XP machines receive the email with the encrypted content as attachments.The only way to read it is to open it in PGP Viewer.
However, other Win7 machines can easily decrypt the message transparently and read it.
If the WinXP machine sends an encrypted email to Win7, the email is not encrypted and is received in plain text. If the Win7 user replies to that same email, the WinXP machine receives the email completely blank.
Apparently all Windows 7 machines running Office 2007/2010 do not face this issue.
Could there be a third party software or plugin in the outlook 2003 machine that could be causing such problems ?