creating symbolic link: Protocol error

Here is the solution in a ticket on virtualbox.org : https://www.virtualbox.org/ticket/10085#comment:32 (Note: Execute "whoami /priv" in console with Administrative privileges)

I have done some Windows research on this bug.

If your user is of the Administrator type (rather than a Standard account), there's no way to run VB with symlinks working without the UAC prompt.

If you have a Standard user account (or if you are willing to switch your account to Standard and create a separate Admin account), the solution exists. You will, however, need admin privileges to accomplish several of the steps (not necesarrily for your user account).

1. Run the Local Security Policy (Win+R, type "secpol.msc", confirm UAC). Then navigate to "Local Policies->User Rights Assignment".

2. Find the permission called "Create symbolic links" and double-click it. Add your user to the list of objects having this permission. Or you can add the "Users" group. Log off and log on. You can check the success by running in console:

   whoami /priv
   

   If you see the privilege SeCreateSymbolicLinkPrivilege enabled, you've done well.

3. Make sure your user has proper access to the shared folder on host system.

4. As mentioned here earlier, execute

   VBoxManage setextradata VM_NAME VBoxInternal2/SharedFoldersEnableSymlinksCreate/SHARE_NAME 1
   

   in a console from the C:\Program Files\VirtualBox folder. Don't forget to substitute VM_NAME with the name of your VM and SHARE_NAME with the name of the shared folder (as it appears in the VM settings).

5. You're done.

If you happen to own one of the "lesser" version of windows (e.g. 7 Home), you don't have the "secpol.msc" utility. See How do I grant SeCreateSymbolicLink on Windows Vista Home edition for help.

It's a problem with the host filesystem. Check the permissions on the host folder are adequate and the the host filesystem supports symlinks.

Right click on your command prompt and "Run as Administrator" (or whatever program you're using to make those symlinks needs to be run as adminstrator).