The ‘Don't add signature if already present’ feature does not work if a signature template only contains an image

Scenario:

You have created a new signature template that only consists of a promotional banner image.


You have assigned the signature template to a policy and configured policy options to not append the signature content if it is already present in the message conversation:



Upon testing, the policy is not applied.

Reason:

The Don’t not add signature if already present option performs a plain text comparison to check if a signature has already been applied. Therefore, if the template only contains an image, there is no text to compare, so it is not possible to identify if the template has already been applied.

Solution:

To avoid this behaviour, add some text to the signature template. If required, you can format this text so the font size is small and colored white, ensuring that it blends in with the email client’s background and that it is therefore invisible to recipients.

Mail Disclaimers Signature Manager Exchange Edition Troubleshooting