S/MIME messages show problems which are not shown in MS Outlook

I am just trying out S/MIME and get error messages for different scenarios:

  1. receiving a signed message from my bank, will result in “signature has problems”. Details show “The message hash differs from signature value.”. MS Outlook 2010 shows no problems with the email.

  2. signed/encrypted mails send by me from eMClient will show up with an signature problem in MS Outlook 2010 (The message contents may have been altered.), but are shown as correct in eMClient (sent items)

  3. Same thing as 2) happens vice versa. If the message is signed/encrypted in MS Outlook 2010, it will show up in eMClient as “encryption has problems” (Local Certifcate: unknow; Chain validation unknown). But interestingly is decrypted anyways.

Any pointers would be greatly appreciated.

PS: Certifcate is from StartSSL and trusted by Windows.
PPS: Version is 6.0.197140. but was not available in the “related product/service” section.


I am very sorry for delayed answer, but I was unable to think of anything better how to help you than just ask you for .eml file (exported email) with this issue, if it is okay for you.

You can send it to [email protected], please send me also url to this topic for easier identification.


The problem is caused by either your code or crypto library. EMClient is not recognizing the signature algorithm.

The cert probably has an SHA2 signature; EMClient only recognizing SHA1.

Also, the OP probably needs to install the bank’s public CA cert.

Hi, i have similar problem with messages sent from thunderbird (signed, Mac OS catalina) to em Client (7.2.35700.0, Mac OS Catalina), in emClient there is no information about signed messages, and can’t import key from this message to use it’s on encrypting replay.
I check in gmail and verification of signed message from thunderbird is ok.
Also sending signed message from emClient to Thunderbird don’t show information that message is signed.

Also I can’t use Mac keychain to remember PGP password, but it’s another subject.