1. Add your user account to the built-in Backup Operators group (or use policy
editor to give yourself the backup right somehow).

2. In a run-as-admin shell, run robocopy with "/b".


- This appears not to affect any filesystem permissions, i.e. the explicit
  permissions on individual files are not changed.

- There is a bug in robocopy that causes /b to disable its ability to copy
  files that are open in another process. See "robocopy bug: error 32 when using backup mode switch"
  and http://social.technet.microsoft.com/Forums/windowsserver/en-US/8abd43b0-ad64-41c7-bca6-691c26c02749/robocopy-bug-with-b-switch?forum=w8itprogeneral