I loaded the GM of 10.11 on my Mac and it completely destroy my use of it. All apps would not launch and reported "You can't open the application 'xxxx' because it may be damaged or incomplete." I manage to get it partially working under a different user ID, recovered some of the usual ID I use, but mounting problems just proved the install damaged the OS and other things beyond repair. So I'm going to grab my data and run like hell back to Yosemite. Screw this crap. I'm presently doing an erase and install. I'm going back to Yosemite since I don't trust the GM release of El Crap-oh at this point. I'm betting that this problem will be Apple's next "gate" and I think that they will probably deserve it. Hopefully it won't turn out that way on Sept. 30th. It would suck for them to have 100's if not 1,000's of user's Macs go belly up.