Just wanted to know if I am the only one having the problem, that Safari 8.0 on Yosemite DP4 doesn't load installed Extensions. When I install an Extension, it works perfectly but after restarting Safari, they are gone. They are still inside the /Library/Safari/Extensions folder but when I want to use them, I need to install them again after every restart of Safari. I tried various methods like deleting pref files and so but still no fix.