In some cases, the activation pop-up that authorizes Arché isn't appearing when you scan your new plug-in(s) in your DAW for the first time. Instead, the plug-in is treated as a corrupt file and blacklisted by your DAW. To fix this, instead of using the internal activation routine, please rely on the more comprehensive software iLok License Manager, which can be downloaded from www.ilok.com.
Please follow the steps in the article: Activating Arché with iLok License Manager
After that, tell your DAW to rescan your plug-ins again and see if the plug-in(s) is/are now showing up.