Offline files that are ghost items on a computer that is running Windows Vista or Windows Server 2008 cannot be synchronized with the corresponding files on a file server
On a computer that is running Windows Vista or Windows Server 2008, you have some offline files that are ghost items. In this situation, you cannot synchronize the offline files on this computer with the corresponding files on a file server. Additionally, you cannot access or delete these offline files.
Note: Ghosting is a new feature for offline files in Windows Vista and in Windows Server 2008. Sometimes, a synchronization process may stop responding because of network issues that occur when the contents of a file or directory are only partly cached. In this case, client-side caching (CSC) creates ghost items on the client computer. Ghost items cannot be deleted. Additionally, the ghosting feature cannot be disabled.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Microsoft KB Article KB949671.