If you use Vagrant on Windows 10, there is big chance of getting error like this when you try to start the machine.

vagrant up
    Bringing machine 'default' up with 'virtualbox' provider...
    ==> default: Clearing any previously set forwarded ports...
    ==> default: Clearing any previously set network interfaces...
    ==> default: Preparing network interfaces based on configuration...
        default: Adapter 1: nat
        default: Adapter 2: hostonly
    ==> default: Forwarding ports...
        default: 19021 (guest) => 19021 (host) (adapter 1)
        default: 4567 (guest) => 4567 (host) (adapter 1)
        default: 3000 (guest) => 3000 (host) (adapter 1)
        default: 3003 (guest) => 3003 (host) (adapter 1)
        default: 6379 (guest) => 6379 (host) (adapter 1)
        default: 9000 (guest) => 9000 (host) (adapter 1)
        default: 27017 (guest) => 37017 (host) (adapter 1)
        default: 22 (guest) => 2222 (host) (adapter 1)
    ==> default: Running 'pre-boot' VM customizations...
    ==> default: Booting VM...
    There was an error while executing `VBoxManage`, a CLI used by Vagrant
    for controlling VirtualBox. The command and stderr is shown below.

    Command: ["startvm", "8dd3dbf3-efe3-4183-98d6-7679f9e83238", "--type", "headless"]

    Stderr: VBoxManage.exe: error: Failed to open/create the internal network 'HostInterfaceNetworking-VirtualBox Host-Only Ethernet Adapter #9' (VERR_INTNET_FLT_IF_NOT_FOUND).
    VBoxManage.exe: error: Failed to attach the network LUN (VERR_INTNET_FLT_IF_NOT_FOUND)
    VBoxManage.exe: error: Details: code E_FAIL (0x80004005), component ConsoleWrap, interface IConsole

The problem appears only when Vagrant is configured to use private_network (i.e. Host-Only Ethernet Adapter). If you change your Vagrantfile configuration so that bridged network is used instead of private one, the machine will boot up without any problem. But how to fix the issue with the private network?
It’s more easy than you can imagine!

1. Go to start menu -> Control Panel -> Network and Internet -> Network and Sharing Center -> click on “Change adapter settings” form the menu on the left sidebar. List of available network adapters will show up.
2. Double-click the “VirtualBox Host-Only Ethernet Adapter” from which the error is comming. Please note that you may have multiple VirtualBox ethernet adapters and so you should read more carefully the error message you get to determine the problematic one.
3. Click the “Properties” button
4. Tick the checkbox for “VirtualBox NDIS6 Bridged Networking driver”
5. Press the OK button.
6. Try vagrant up command now. The machine should boot normally.

Voila!