After updating to Win10, I learned there was also an update to Bootcamp. I have tried several times to update, to no success. It sits in "Apple Software Update" and will not complete the update. Then when I try to close "Apple Software Update", it will not close the installer unless I do a hard restart. From a Google search I observed many other people are facing the same challenge, but i did not find a solution.
MacBook Air, Mac OS X (10.7.5), I have the most current version