I upgraded Parallels 10 early today, then able to install Mac OS X Yosemite as guest OS on Parallels 10, however, try many times to install the OS X 10.10 Update 1, but all failed. Could anyone advise how to fix the issue. Million thanks in advance. Cheers, Barry
Finally I found the solution - download the DP 5 from Apple Store, and install DP 5 over OS X Mavericks (10.9.1), then apply DP 6 successfully. Now I'm running OS X Yosemite DP 6 as gust OS on Parallels 10.