TFS get command erroneously returns “All files are up to date.”

We are just in the process of migrating our TFS repo to Mercurial as we've had enough of TFS. Unfortunately TFS has thrown us one last curve ball before it lets us go. We've wrote a script that we intend to have "get" each changeset (including timestamp, check-in comment etc) and then add them to the Mercurial repo and check it in.

Unfortunately TFS is acting very strange when we execute the tf get * /version:C111 /overwrite command. It immediately returns "All files are up to date." But this is impossible. The workspace folder is empty! And viewing the details for the 111 changeset quite clearly shows that the changeset contains "stuff" i.e. the repo is certainly not empty.

What could be causing this?