I installed this morning on three computers without issue. I installed as administrator.
It's different for every PC/OS/IT settings/AV product/settings
Currently, on my development PC, I can install it w/o tweaking anything. But I know some day, some update (to one or more items in the list above), I may be trying to figure out why my install did not work.
1. Run As Admin
and if that doesn't work
2. Disable AV (but get off the Network/Internet beforehand - it's amazing how many things are out there CONSTANTLY trying to hack into your PC, because it can)