iMac locks up on restart and will not complete start up
I downloaded an update for OS X 05 July 2015 and Digital Camera RAW Compatibility Update 6.05 on 10 July 2015. Now I cannot start IMAC. I have tried OS Recovery but it locks up 1/2 through startup on the Progress Indicator. Any recommendations would be appreciated.
I am not able to provide iMAC data because it is locked up in the start up process.
iMac, OS X Mountain Lion (10.8.5)