I have two MacBook Pro mid 2013, same hardware inside. In the first one I had the following sequence of OSs. Mountain Lion (factory) > Mavericks > Yosemite > El Capitan > El Capitan (Clean Install)
And whenever I start the Mac I have this flow Apple Logo > User login (my user + guest user) > Loading (progress bar) > OS loaded
In the second MacBook I had Mountain Lion (factory) > El Capitan
And this flow at start Apple Logo > Loading (progress bar) > User login (my user + guest user) > OS "lazy" loaded ("lazy" = Status bar is loaded a few seconds after the screen with dock is presented)
Since there is a clearly difference in the behaviour of the two OSs, my question is: why does this happen? Is there a problem with one of the OSs? Which is the correct flow?