Mac 13'mid2010 with Sierra problems
Hi, I upgrade to El Capitan then to Sierra, but now is not running well. Should I go back to El Capitan? Can I? Also pops up a sign "To use the Java command-line tool you need to install a JDK" every time I turn on my Mac. Thanks for your help (You can reply in Spanish too)
MacBook Pro, macOS Sierra (10.12.6)