Hello - I am now desparate having checked both Adobe and Apple forums as I have tried to upgrade Flash on my Imac Mountain Lion 10.8.5 (Safari 6.1) and continually get General Installation errors. I have followed every thread that I can find on this (including the classic how to do a clean install of Flash) and cannot get past 55% installation before it crashes. This happens every time without fail.
Done a clean install of Mountain Lion, switched accounts and nothing works. Simply cannot download Flash.
if anyone can help that would be amazing!
Odds are, you inadvertently deleted the mach_kernel file that the 10.8.5 update made visible.
That's been the cause of the "General Installation Error" since the update was released.
See: http://forums.adobe.com/thread/1318151 for instructions and a download that may help.
Many people have had to reinstall their OS, but some were able to remedy it by downloading and installing OS 10.9 (it's free, so it couldn;t hurt to try if the other fix doesn't work)