Hi, Tried using WMP11 Slipstreamer v1.2.4.0 to slipstream to XP SP3 but got the following unhandled exception. The application suggested that I report this as a bug so... Anyone any ideas what I might be doing wrong? I suspect it's probably more my own fault. Many thanks! WMP11Slipstreamer v1.2.4.0 Detected source: Windows™ XP Professional SP3 Hotfixes: WindowsXP-KB941569-x86-ENU.EXE windowsmedia11-kb928788-x86-intl.exe windowsmedia11-kb929399-v2-x86-intl.exe windowsmedia11-kb929773-x86-intl.exe windowsmedia11-kb932390-x86-intl.exe windowsmedia11-kb933547-x86-intl.exe windowsmedia11-kb935551-x86-intl.exe windowsmedia11-kb935552-x86-intl.exe windowsmedia11-kb939209-x86-intl.exe WindowsMedia11-KB939683-x86-ENU.exe windowsmedia11-kb944110-x86-intl.exe windowsmedia11-kb944882-x86-intl.exe windowsmedia11-kb945381-x86-intl.exe windowsmedia11-kb946665-x86-intl.exe System.Exception: Delta API failed to apply patch "_sfx_0001._p" to the file "update.exe". ---> System.ComponentModel.Win32Exception: The requested operation cannot be performed on a file with a user-mapped section open --- End of inner exception stack trace --- at WMP11Slipstreamer.Backend.NativeExtractHotfix(String hotfixInstaller, String destinationPath) at WMP11Slipstreamer.Backend.ExtractWMP11Installer() at WMP11Slipstreamer.Backend.SlipstreamWMP11() at WMP11Slipstreamer.MainForm.WorkerMethod(Object workerParam) Deleting "C:\XP\i386\wmp11temp"... FAILED! An exception occurred while attempting to delete the temporary folder to revert the changes done to the source. You can delete the temporary folder by yourself later. Temporary folder: "C:\XP\i386\wmp11temp" System.UnauthorizedAccessException: Access to the path '_sfx_.dll' is denied. at System.IO.Directory.DeleteHelper(String fullPath, String userPath, Boolean recursive) at System.IO.Directory.Delete(String fullPath, String userPath, Boolean recursive) at WMP11Slipstreamer.ErrorForm.ErrorForm_Load(Object sender, EventArgs e)