IntranetSSL certificates on unmanaged Macs

These instructions assume you are running a modern-enough (read: supported) version of macOS, and a supported version of your favourite browser that is Firefox, Safari, Chrome, or Edge. If your macOS version is under 13 or you are running older versions of these browsers (see end of document), upgrade either or both, and come back. (Note that in May 2024, when I write this, macOS 12 is still supported. You should still upgrade, as support for that will likely be dropped in less than a year.) These instructions are for macOS 14, but should work for 13 as well.

Go to the GlobalSign intermediate certificate page:

IntranetSSL Root & Intermediate Certificates :: GlobalSign Support

Get the SHA256 intermediate and root certificates, clicking the “download certificate” buttons.

You will get a couple of .crt files in your Downloads folder. Open the folder up, then double click each file. You will get a popup like this, choose System from the drop down. You will be prompted for your administrator password.

This will open Keychain Access. Type “Globalsign” into the search bar. You are looking for the “GlobalSign Non Public” certificates.

For each certificate, right click, Get Info, and then click the arrow next to Trust. On the dropdown next to “When using this certificate:” select “Always Trust”. The other options will automatically change.

Then you can close the window (you will again be prompted for your administrator password). Repeat for the other certificate. Once this is done, you can close out of Keychain Access. If you had any browsers open during this process, restart them. All supported browsers in supported versions of macOS should support the operating system trust store, and so you should not encounter any errors. In an unsupported browser, or perhaps one that has been upgraded from prior versions, you will need to (in general) look for preferences related to certificates or security, and look for settings involving “operating system trust store.”

Supported browser versions:

· Firefox: 126.0

· Chrome: 125.0.6422.61

· Edge: 124.0.2478.105

· Safari: depends on operating system version