Q:

vagrant under cmder on Windows 10 does nothing; works under cmd.exe

I have a fresh Windows 10 64-bit install, which I'm attempting to set up for development.  
I have 

downloaded and installed cmder, then rebooted
downloaded and installed Vagrant, then rebooted
downloaded and installed VirtualBox, then rebooted
set VAGRANT_HOME=c:\vagrant
used VBoxManage setproperty machinefolder c:\virtualbox-machines
acquired my department's VagrantFile, and modified it to suit my filesystem. 

In cmder, if I now run 
vagrant box add http://opscode-vm-bento.s3.amazonaws.com/vagrant/virtualbox/opscode_centos-7.0_chef-provisionerless.box --name chef/centos-7.0

I get no output.  No failure codes, no windows errors, no logs from vagrant.  The same is true of all vagrant commands, up to and including vagrant --version and vagrant --help.  Other commands work fine in cmder. 
However, if I run a basic command line, cmd.exe, then the vagrant box add command completes correctly.  An, as far as I know, identical setup worked under Windows 7 32-bit. 
Can anyone suggest what might be going wrong? 

A:

There is something wrong with the git-for-windows that is vendored with cmder and vagrant.  However, cmder allows you to have your own install of git-for-windows. 
To fix this issue with vagrant working and cmder:

Install git for windows from https://git-scm.com/
Ensure your PATH includes the path to the git you just installed (default should be: C:\Program Files\Git\cmd)
Restart cmder

Cmder should then detect the custom git install and use that and there will no longer be a problem with vagrant. 
Editing the cmder vender\init.bat is not a great solution because this can be replaced by cmder in a future update.