Last update January 31, 2023
If plug-in you've just installed doesn't show up on plug-in list in Ableton Live first of all make sure all Software Requirements are met by your setup.
Try out the solution described in this entry at our FAQ. It's possible that some system runtime libraries required by plug-in are missing. This concerns especially relatively fresh Windows installations.
Still no success? Open Ableton Live's Preferences and go to Plug-Ins tab. Click Rescan button while holding Alt key (Windows) or Option key (MacOS). This will force Albeton Live to perform much thorough plug-in scan. This concerns both platofrms: Mac OS X and Windows
if you're macOS 10.13 High Sierra user and utilize Audio Unit format of the plug-ins, check out this entry at our FAQ