I have just installed El Capitan in my iMac. I no longer have internet access, either through Safari, Firefox, Apple Mail, Norton Internet Security (NIS), Contacts, etc. Furthermore, Parallels and Windows 10 are installed in my iMac. I no longer have internet connectivity on the Windows side of my iMac. I would appreciate it if someone could help me to solve this problem. Please note that participants in another thread in this web site complained that NIS was not compatible with various betas of El Capitan. When NIS was running they had no internet access, and when they disabled it internet access was restored. Is that the problem, here? I thank you for any advice you can give me. Update: I have just phoned Norton product support. The tech told me that Norton Internet Security is not compatible with El Capitan. He told me that "they are working on it" and recommended that I call back in one month. MacRumors: PLEASE WARN YOUR READERS WHO USE NORTON INTERNET SECURITY NOT TO INSTALL EL CAPITAN, until Symantec comes out with a fix!