I am trying to install several addons to my blender 2.79 under OSX. I have the addons as zip files. I follow the documented process, go to the settings, click on install from file, select the file, I can read a message in the bottom of the screen where blender says that it is copying the addon.
Unfortunately, the addon does not appear in the list of addons afterwards, I checked the folder in the user library and the addon has been copied there but it does not show up in blender.
Any idea, how I can debug this! Is there a log file that I could look into?