mail.app
I have lost patience with outlook and have started using apple mail with my corporate exchange account.
A problem is that every mail I send by default picks up an ios developer certificate that i have associated with this e-mial address.
I know you can click on the button on each mail to turn off signing that message, but i'd like the default to be NOT to sign each message i create.
J
Setting Default mail Client tells your system to use that one when requesting email from other applications. (outside of Email).
While in Email (Outlook or Mail) they will do as told.
In your case using MS Office Word, Excel, PowerPoint with email link in one of the documents, will by default use the chosen default mail client.
There is a simple work around. Since you are probably not using heavy duty MS Office applications to handle your Mail.app but do so with Outlook, I would make the Outlook the default mail application. Now you can use Mail as email and Outlook will be the default mail client for your work.
I have some email accounts that use S/MIME and some that use GPG. When I select to use the email address configured for GPG, GPG email signing is enabled by default. When I select to use the email address configured for S/MIME, the S/MIME email signing is enabled by default.
I had to enable some settings in the GPG preference section of Mail.app, but nothing else.
Best Answer
Try this. Go to your your Preferences of the Mail application. Then, you should be in the Account section. Choose your account then at the very bottom change TLS Certificate to "None".