https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-setfilevaliddataThe SetFileValidData function allows you to avoid filling data with zeros when writing nonsequentially to a file. The function makes the data in the file valid without writing to the file. As a result, although some performance gain may be realized, existing data on disk from previously existing files can inadvertently become available to unintended readers. The following paragraphs provide a more detailed description of this potential security and privacy issue.
A caller must have the SE_MANAGE_VOLUME_NAME privilege enabled when opening a file initially. Applications should call SetFileValidData only on files that restrict access to those entities that have SE_MANAGE_VOLUME_NAME access.
其实就是默认只允许具有特定权限的应用调用，调用后果是分配磁盘但是不初始化，所以磁盘上之前的数据如果去读区的话，可能会出现安全问题，比如如果那片空间如果保存过密码啥的。但你信任 arial2，所以其实没啥问题。