I updated from Mavericks (10.9) to Yosemite (10.10) on a Macbook Pro 2009 with a Samsung SSD.
The notification I get is:
Line 6 Monkey can not be installed on this drive. This software requires Mac OS X 10.5 or above.
My guess is that 10.10 in an alphabetic field compared to 10.5 in an alphabetic field is considered a lower value.