This article might be helpful to anybody who satisfies the following criteria:

• Wants to run Grunt
• On a Mac
• Running Linux through VirtualBox
• Using a shared folder for the directory you want to install packages

If this describes your situation, you probably have run into errors installing the local version of Grunt through npm

The reason for these errors might be that your Shared Folder doesn’t actually support symlinks.

This was a change in v1.8 of VirtualBox. It is a security precaution. If you’re willing to waive the security concerns, the solution is as follows:

• Shutdown your VM
• Quit VirtualBox
• Enter the following in the terminal

   VBoxManage list vms

• Copy the name of the virtual machine in question
• Then enter:

  VBoxManage showvminfo "VM Name"

• From the output, look for the name of the Shared folder you wish to allow symlinks for, copy it
• Finally, enter the command:

  VBoxManage setextradata "VM Name" VBoxInternal2/SharedFoldersEnableSymlinksCreate/"Shared Folder Name" 1

• Start up your VM again and you should have symlinks working on your shared folder :-)