Hangs after clicking "Restart" when trying to upgrade to 10.10.4

[ownself]

I've used Tonymacx86's hackintosh for 4 years, it works perfect on my PC, from 10.7 to 10.10.3, recently I met a problem when I was trying to upgrade to 10.10.4, I was trying to upgrade with App Store, after downloading, It says need me restart to finish the upgrading, as usual, but 2-3 seconds after I clicked "Restart", It hangs at a black screen with a freezing cursor on the screen, hard drive LED doesn't flash at all, and nothing happened in about 15 mins.
Then I manually restart the system, it still shows 10.10.3 and everything looks normal as same as before.

I also tried with downloaded "10.10.4 Combo Update" and "10.10.5 Combo Update" but got same result.

Anyone met same problem? If I can't get over with this, probably only thing I can do is making a clean re-installation after 10.11 released. I upgrade system from 10.9 without any clean re-installation for 2 years. I have to say even something I met weird problem, but still TonyMacx86's hackintosh is really stable and reliable!! I have to say thank you !!!

 

[ownself]

OMG! I tried so many times, it didn't work, just after I finished this thread, I shutdown my PC, after I clicked the button, upgrading UI came up and it started to upgrade!!

I have no idea, but everything works fine now.....