I thought I would try El Capitan yesterday - it installed fine but after that, things were not so rosy! First, Safari would not open my normal web sites. Facebook, Twitter, Youtube, Yahoo and a local radio site to my location would not open. I reported via feedback regarding the issue and sent screenshots where possible. Mail was working but as the evening progressed it simply died. The mail could not connect to Apple, Yahoo or Gmail to get email. That kinda ended my lack of testing. I have downloaded Beta in the past i.e. Yosemite, and this has never happened to this extent. I would expect crashes and some programs not to work but this I did not expect. I truly hope I am alone with these symptoms. Perhaps there were other issues - antivirus for example that was preventing the system from working - don't know. I could deal with a browser not working but email is kinda a show stopper. I backed out this AM and put 10.10.4 back on from a backup.