vagrantがエラーを吐いて立ち上がらなくなった。症状はこちら。

$ vagrant up
/opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:127:in `downcase': invalid byte sequence in Windows-31J (ArgumentError)
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:127:in `block (2 levels) in fs_real_path'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:126:in `each'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:126:in `block in fs_real_path'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:125:in `each'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/util/platform.rb:125:in `fs_real_path'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/lib/vagrant/environment.rb:120:in `initialize'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/bin/vagrant:165:in `new'
	from /opt/vagrant/embedded/gems/gems/vagrant-1.7.4/bin/vagrant:165:in `<main>'

ググると、こういう解決策が。

export LANG=ja_JP.UTF-8

via! http://www.eelingshi.com/questions/2864996/vagrant-up-fails-and-error-is-invalid-byte-sequence-in-windows-31j-argument