If you receive an “Error 11” when VPOP3 Antivirus is attempting to upgrade, then this means that it cannot download the antivirus updates from the Internet

1. Make sure you are using the latest version of the VPOP3AV plugin. You can check the version in the Settings → Antivirus page in the VPOP3 settings, and the latest version can be downloaded from https://www.pscs.co.uk/products/vpop3/av/download

1. If that doesn't work, in the VPOP3\plugins\vpop3av folder, edit the 'vpop3avu.conf' file in a text editor (eg Notepad) and add this line to the end of the file if it does not already exist:
   DatabaseMirror avupdates.pscs.co.uk