emails not downloading to Mac Mail

I have recently found that my emails are not being received by my Mac Mail from my account with the ISP Virgin Media, although I was able to send emails. At first I blamed Virgin but, after much investigation, I tried turning off the Mail Shield and, lo and behold, all my emails appeared on my Mac. Is this a SSL related issue? There were problems in this area with an earlier version of Avast but then it issued error messages so you knew where the problem was. With my current problem I get no indication that anything is wrong, I just do not get my emails. I am now having to operate without the Mail Shield unless anybody can advise a suitable course of action or until Avast is fixed.

Uninstalling Avast! (from the Avast menu) and reinstalling it (using the latest version) will likely fix this problem, I think it has to do with Avast! certificates being used for the SSL connections (reinstalling regenerates them).

Thanks for that - I will give it a try although I had checked that I was using the latest version of Avast. It seems to be since installing the latest version that I have had trouble.

Are there any related error messages in the system log (/var/log/system.log)?
What mail client and protocol (IMAP or POP3) do you use?
What mail server are you connecting to?

Unless You provide us more info so we can reproduce the issue, there is nothing we can
do with this issue.

OK, I am using a Macbook Pro running OS X 10.6.8. My mail server ISP is Virgin Media and I am receiving mail via Mac Mail using IMAP protocol with SSL on. With the Mail Shield on my messages do not come through or are at best intermittent and I do not get any error messages. If I try using Thunderbird, again the messages do not arrive but in the log there are error messages about duplicate serial numbers on certificates. I have tried uninstalling and re-installing Avast but to no avail so I have turned the Mail Shield off again. Please let me know if there is any other information you require that might help in resolving this issue.

As already requested, we need at least the messages from the system log file. Please post here the output of
the following command (after you enable the mailshield and try to fetch mail):

grep 'com.avast.proxy' /var/log/system.log

Sorry, I hope this is what you want:

Sep 2 19:36:44 com.avast.proxy[51]: Starting daemon.
Sep 2 19:36:51 com.avast.proxy[51]: Error opening log file: /var/log/avast/proxy.log: No such file or directory
Sep 2 19:36:51 com.avast.proxy[51]: client.dropbox.com:https: nodename nor servname provided, or not known
Sep 2 19:39:02 com.avast.proxy[51]: Error reading receive buffer: read(): Connection reset by peer
Sep 2 19:40:00 com.avast.proxy[51]: Error reading receive buffer: read(): Connection reset by peer
Sep 2 20:15:06 com.avast.proxy[51]: SIGHUP received. Restarting.
Sep 2 20:15:06 com.avast.proxy[51]: Error opening log file: /var/log/avast/proxy.log: No such file or directory
Sep 2 20:20:48 com.avast.proxy[51]: SSL_read(): EOF
Sep 2 20:30:47 com.avast.proxy[51]: SSL_read(): EOF