OS X 10.15/Catalina introduced a much more aggressive security model. This article explains how to resolve the following security dialog when loading Triple Triangle plug-ins:
Your deployment email will contain two links. One to a zip file containing your custom deployment (including custom slugs, licenses, and .InDesignPlugin files for anyone not using Catalina). The second link is to a .dmg file containing only our InDesign plugins. Starting in Catalina, you must download the .dmg, and copy the Plug-ins from it into the TripleTriangle folder included in the zip. The .InDesignPlugin files in the .dmg will replace existing files.
The files in the .dmg have been properly notarized with Apple. When you download and mount the .dmg, Catalina can verify that the executable software in the Plug-ins is valid and free from viruses. This resolves the security error above.
Starting in Catalina, executable software must be 'notarized.' Notarization can only be done on a .dmg. Apple clearly intends for each version of a piece of software to be notarized once, and not for us to notarize a different .dmg for every customer. We considered creating a notarized .dmg for every customer, but were afraid the volume of notarizations would eventually lead to issues with Apple.
If you have difficulty executing these steps, or they don't work for you, please email us at firstname.lastname@example.org.