Sometimes in Logic, after the install, you need to manually force the validation of a plug-in in the AudioUnits Manager. It might show as "validation failed" (or somethlng similar), but if you click on the particular plug-in and force a new validation of that plug-in, it should change to "validation passed" and show up in Logic on the next Logic launch.
If it's still not working after that, you might have to re-install the plug-in.
But first, completely remove it from your computer.
On Mac OS X, follow this procedure:
1. in standalone mode, backup your potential data (presets, banks) using "Export" entry on the <synth> front panel, and close the software;
2. when applicable, remove your dongle from the computer, and make sure no application using the Syncrosoft protection system is currently running;
3. remove <synth> files from the following directories:
Standalone : /Applications/Arturia <synth>/
VST : /Library/Audio/Plug-Ins/VST/<synth>.vst
AU : /Library/Audio/Plug-Ins/Components/<synth>.component
RTAS : /Library/Application Support/Digidesign/Plug-Ins/<synth>.dpm
Sounds and Prefs : /Library/Preferences/<synth>/
Installer : /Library/Receipts/<synth>.pkg
4. reinstall the <synth> directly from the update:
==>
http://www.arturia.com/evolution/en/downloads/updates.html5. for the ARP2600/CS-80V/MgModularV, *only when prompted* put the original disc in your drive, and enter the license number.
6. for the Jupiter-8V/ProphetV/AnalogFactory/miniMgV2, reinstall the Syncrosoft License Control Center directly from the update:
==>
http://www.elicenser.net7. when applicable, plug your dongle and launch the software.
8. import your potential data using "Import" entry on the <synth name> front panel.