Hi Peter,

When you say Excel can't 'see' the certificate what exactly do you mean?

When you try to add the cert in the VBA editor are you getting an error 'No usable signing certificates are available. Please insert your smart card, or contact your administrator to obtain a signing certificate' ?

Have you installed the cert in your PC using Certificate Manager?

Have you tried creating a self signed cert and installing that, just to test if it's an issue with the DigiCert cert?

Reading up on this there was a bug in Office that prevented Excel seeing certs.  Have you got Office up to date?  What version are you using?

Regards

Phil