I don't think this in any way reduces protection, as the real-time background scan of email is still in place. Sfhowes said There are plenty of references if you Google Sophos SSL scanning, and advice for adding exclusions. The problem with this whole thing is that the warning is very scary with no solution provided. I have no idea how to disable SSL scanning but in looking it up it says that you are effectively turning off the virus protection. The only difference is that the Common Name is now DigiCert Cloud Services CA-1. So, after I sent the post you replied to, I unistalled Avast and went back to Sophos, but it's still doing it. A few days ago, I removed my Sophos virus protection and replaced it with Avast because I wanted protection I could turn off when need be and this is easier to do in Avast. Disable SSL scanning and see if it helps: Openssl s_client -connect quantumwarp.Do you have Avast intercepting certificates? That is probably the source of the error. If using on windows you will need to get the binary file openssl.exe openssl s_client -connect host:port -showcerts you will get the warning message on load up you can also check the certificate details in outlook if it is faulty.disable the SSL scanning and then recheck the ssl certificate is correct.adding the account and re-adding it in outlook did not work.

when you click install it is never installed permanetly (only if it is expired?).it is avast issuing a certificate from its system on the fly.i cannot find the certificate for .uk in my ssl store.re-installing the mail component does not fix this (including a reboot).The instructions below are what helped me come to that conclusion. As it happens the certificate at the other end was out of date and Avast mints new certificates on the fly so there is no cache to worry about. I had this issue with an SSL certificate that I thought was correct at the remote server and that Avast Antivirus had then flagged as out of date.

Now if you examine the certificate: This certificate has expired or is not yet valid When using Outlook you can also see this error: The downside to this is that all certificates appear to be signed by avast! Web/Mail Shield Root and can make things confusing at first glance when a SSL certificate is out of date. When you use Avast Antivirus it installs an invisible proxy SSL Certificate Authority that allows it to scan SSL/TLS traffic with its antivirus engine.

Outlook avast certificate error