I created a self signed S/MIME for encrypted emails in OSX Keychain Access. I am using this S/MIME on my iPad (iOS 8.1) and on my iMac (OS X 10.10). With this S/MIME I have no problems on the iPad decrypting emails which were sent from devices running iOS or OSX. But when receiving encrypted emails from a Windows PC I get the following error message: "Decryption Error. This message is encrypted. Install a profile containing your encryption identity to decrypt this message" The iMac, using the same S/MIME, has no trouble decrypting the same email sent from the Windows PC. Does anybody have the same issue? Does anybody have a solution for this problem?