I did a completely clean new Windows installation, and then copied my
 Pegasus Mail across. That should have annihilated Norton, whilst 
maintaining all Pegasus settings. As a result, I imagine that there must
 be something wrong with my Pegasus setup to cause this issue.
Regarding
 AVG, I installed the free 2012 version and didn't do any additional 
setup. I did noticed, whilst trying to understand it better now, that 
according to AVG, exactly 0 emails have been scanned since installation,
 so I gather that I need to change that setup :-). I do not have the 
virscan extension installed. Apart from the virus checker and the 
standard Windows Firewall I have nothing sitting between me and the mail servers.
I will need to double-check the log regarding delays - will get 
back to you on that. However, could you help with the Content Control 
settings? I was trying to find a forum posting to figure out how/what to
 change to 5000, but haven't been lucky... what do I need to do? Given that I have only ever actively used Spamhalter, I am not in any way au fait with Content Control.
 
        <p>I did a completely clean new Windows installation, and then copied my
 Pegasus Mail across. That should have annihilated Norton, whilst 
maintaining all Pegasus settings. As a result, I imagine that there must
 be something wrong with my Pegasus setup to cause this issue.</p><p>Regarding
 AVG, I installed the free 2012 version and didn't do any additional 
setup. I did noticed, whilst trying to understand it better now, that 
according to AVG, exactly 0 emails have been scanned since installation,
 so I gather that I need to change that setup :-). I do not have the 
virscan extension installed. Apart from the virus checker and the 
standard Windows Firewall I have nothing sitting between me and the mail servers.
</p><p>I will need to double-check the log regarding delays - will get 
back to you on that. However, could you help with the Content Control 
settings? I was trying to find a forum posting to figure out how/what to
 change to 5000, but haven't been lucky... what do I need to do? Given that I have only ever actively used Spamhalter, I am not in any way au fait<span class="st"><em></em></span> with Content Control.
</p>