I was working with a senior support person at Apple this morning and discovered that the reason my Mac wasn't sleeping any longer, after the install of El Capitan, was because of the antivirus software. Uninstalling Avast did indeed fix the sleep problem.
I also noticed that on your website it says that Avast will work with all versions of OS X including Yosemite. No mention of El Capitan. Is Avast not usable with El Capitan then?
