Se você chegou até aqui, você com certeza já se deparou com esse erro irritante quando você tenta retomar um download que falhou?

PS D:\vagrant> vagrant init rasmus/php7dev  
A `Vagrantfile` has been placed in this directory. You are now  
ready to `vagrant up` your first virtual environment! Please read  
the comments in the Vagrantfile as well as documentation on  
`vagrantup.com` for more information on using Vagrant.
PS D:\vagrant> vagrant up --provider=virtualbox  
Bringing machine 'default' up with 'virtualbox' provider...  
==> default: Box 'rasmus/php7dev' could not be found. Attempting to find and install...
    default: Box Provider: virtualbox
    default: Box Version: >= 0
==> default: Loading metadata for box 'rasmus/php7dev'
    default: URL: https://atlas.hashicorp.com/rasmus/php7dev
==> default: Adding box 'rasmus/php7dev' (v0.0.8) for provider: virtualbox
    default: Downloading: https://atlas.hashicorp.com/rasmus/boxes/php7dev/versions/0.0.8/providers/virtualbox.box
==> default: Box download is resuming from prior download progress
    default: Progress: 0% (Rate: 0/s, Estimated time remaining: --:--:--):--)
An error occurred while downloading the remote file. The error  
message, if any, is reproduced below. Please fix this error and try  
again.  

Para solucionar esse problema, é necessário apenas remover o arquivo que foi parcialmente baixado, para fazê-lo basta executar o seguinte comando em seu powerShell.

PS D:\vagrant>rm ~/.vagrant.d/tmp/*