WRP also protects several critical folders. A folder containing only WRP-protected files may be locked so that only the "trusted installer" is able to create files or subfolders in the folder. A folder may be partially locked to enable administrators to create files and subfolders in the folder. Essential registry keys installed by Windows Vista are also protected. If a key is protected by WRP, all its sub-keys and values can be protected. Also, WRP copies only those files that are needed to restart Windows to the cache directory located at . Critical files that are not needed to restart Windows are not copied to the cache directory, unlike Windows File Protection which cached the entire set of protected file types in the "Dllcache" folder. The size of the cache directory and the list of files copied to cache cannot be modified.