However, if you have decided to use Microsoft Outlook for S/MIME, you find that Encryption Desktop tries and fails to verify and decrypt inbound S/MIME messages.
Add the policy option passthroughInboundSMIME to each relevant consumer policy. This will cause Encryption Desktop to ignore inbound S/MIME messages. To do this:
In terms of outbound messages, Encryption Desktop will only try to encrypt or sign these using S/MIME if you use the Encrypt and/or Sign buttons or include specific text such as [pgp] in the Subject.