Because of an update made to the installer technology (Arturia Software CEnter), and since the only way to install and activate is through that installer, and that installer crashes at launch time on OS X 10.11, that effectively junks all remaining computers in operation where that instrument is installed. I also sent a technical support request message to confirm if Arturia meant to hose all us users with older Macs, or not, but I thought I'd post a heads up in case anyone else who previously had their apps all installed and working, and found that it has deactivated, and wants you to update your ARTURIA SOFTWARE CENTER, after updating that, it won't even launch that, and so there is now now way to activate anything anymore.
The message says I don't own a license, but that's not actually true, of course I can see the license on the website but as I can't run Arturia software center (it just crashes at startup), I can't activate or install or reinstall.