OSX 10.10: Is it normal to have a loading progress bar at each startup

Question

My MBP-13 (Mid 2010) has become very slow on startup and each time I start (from cold or re-start) it has a "process bar" as if an update is loading, on the Grey Screen where previous to the update there was just the Apple Logo. This began when I upgraded to Yosemite. Admittedly, my hard drive is a bit full (51 GB remaining) and that could be partly to blame for the slower startup, I feel like something is not quite right since the update. Earlier today on the left pane of my finder window, there were 5 versions of this MBP under the "Shared" column (5 versions of itself!). I thought this was strange so I did a restart and while it did take care of the 'ghost' shared versions of itself, it was still slow to startup again, and the progress bar was there again during the grey screen part of the startup process, as it is each time the computer starts.
So My questions are:
1. Is it normal to have that progress bar during startup with Yosemite when it was never there before the update?
and
2. What would cause this computer to show what I like to refer as 'ghost' versions of itself under the shared column on its own finder window left pane?
Thanks in advance for any wisdom you may impart.
Regard,
Capt Ron

Answer 1

1. Yes, the progress bar replaced the spinning gear. Haven't a clue why, but might be to mimic iOS devices ( I don't have any, so can't check).
2,  Can't answer, since I share nothing.
27" i7 iMac (Mid 2011) refurb, OS X Yo (10.10), Mavs, ML & SL, G4 450 MP w/10.5 & 9.2.2