Internet Explorer 7/8 runs in Windows Vista and Windows 7 in special Protected Mode. It gives the following effect: if host from which a page is loaded is not in the list of trusted sites, Internet Explorer is not permitted to get access to arbitrary folders and files. To avoid this problem the control checks a web site where it resides. If it is not in trusted zone, File Downloader acts in the following way:

  1. Download files to temporary folder where Internet Explorer has write permissions (AppData\Local\Microsoft\Windows\Temporary Internet Files\Low);
  2. Move these files to destination folder using special Windows API. This operation requires higher integrity level then Internet Explorer has, therefore Vista requests the user to elevate privileges.

However, it applies a restriction on number of downloaded files. The maximum number of files which can be processed by this API is 500. If a user tries to select more than 500 files, the following message will appear:

Sorry, but you cannot download more than 500 files in Internet Explorer Protected Mode. Please contact web site administrator for more information.

This text message can be localized using the MessageMaxFileCountExceededText property.