Hi Everyone, I have a macbook retina 2012, I had el Capitan and I installed macOS Sierra (10.12). I have the following issues: 1) bluetooth is not available and its pane is missing (please see the snapshots). 2) When I try to add a network interface I got a preferences error: "There was an error in Network preferences." 3) When I try to open a folder, Finder crashes and the folder is opened at the third or fourth trial. I reset smc, nvram, I removed some preferences files and I still have the same issues. Any help would be really appreciated. Thank you!