OSX Yosemite black screen when booting

[Artmuzz]

I updated from OS X Mavericks to OS X Yosemite on my rMBP (late 2013 model with 16GB ram)and I find that the booting time is very slow compared to Mavericks. When Mavericks was on my rMBP it used to take around 3 seconds to boot now since I have installed Yosemite it boots into a black screen for about 20 seconds before the Apple logo appears.

 

[YN36]

I updated from OS X Mavericks to OS X Yosemite on my rMBP (late 2013 model with 16GB ram)and I find that the booting time is very slow compared to Mavericks. When Mavericks was on my rMBP it used to take around 3 seconds to boot now since I have installed Yosemite it boots into a black screen for about 20 seconds before the Apple logo appears.

the same thing happens to me i have a late 2012 rMBP

 

[Artmuzz]

Maybe it has something to do with the retina MacBook Pro models.