Updated Yosemite, now I can't boot into OS X
I updated OS X Yosemite and when I restarted the Mac Mini the progress bar doesn't move past a certain point.
I have had no major issues with the 2012 Mac Mini (i7 2.3ghz, 16gb ram, 1TB) previously, and have updated perfectly ok in the past, including beta versions.
Any helpful suggestions are welcomed and greatly appreciated, thank you.
Mac mini, OS X Yosemite (10.10), 2012