My host machine is windows 8.1 64bit and I started experiencing the same problem yesterday. I cloned each repo and only changed one line in the Vagrantfile as per this post : Deploying from windows
The vagrant-winnfsd also stays running sometimes after a vagrant halt.
I’m not entirely sure what I did that fixed it. I destroyed the vagrant boxes, cleared them out using the virtualbox GUI, and rebooted. Then reinstalled and voila.