Error: "You have not chosen to trust 'AddTrust External CA Root'" when attempting to use Citrix Receiver on your Mac


Symptoms

You receive the following error message when attempting to open an app through Citrix Receiver on your Mac:

You have not chosen to trust "AddTrust External CA Root", the issuer of the server's security certificate.

Contact your help desk for assistance.

example screenshot

Cause

Your Mac's root certificate for AddTrust External CA Root is expired or you are using outdated Citrix client software.

Resolution

1) Uninstall Citrix Receiver.

2) Upgrade to the latest version of macOS. This will update your Mac's root certificates, which may have expired.

3) Install the latest version of Citrix Workspace. Citrix Workspace has replaced Citrix Receiver.


OUTCOME

You will be able to use Citrix app virtualization at TTU without receiving an error message.

Workaround

Use a different device (e.g., Windows PC, iPhone, iPad, or Android device) to access Citrix app virtualization at TTU.