Hi!
I have OS X.10 Yosemite, and my problem is that Norton Toolbar doesn't install on Safari 8.0.2. The problem persist on Safari 8.0.3.
But I remarked on another of my MacIntosh, that that the reverse process is possible: If I install Norton Toolbar, and then the updates - it works - and Norton Toolbar is kept.
So a bypassing solution could be: retrograde the update with a re-installation (by example with the restauration partition, kept in X.9 Mavericks as I installed X.10 Yosemite thank to a download (and not a USB key) what add to the problem), adding Norton Toolbar, and make the updates.
But is there a better (more rapid) way, as the availability of the latest Toolbar Download ?