If AutoUpdater.XML's URL set without a filename suffix, Like 'http://10.10.10.10/' and it redirect to a valid URL which contains the ZIP file. The update dialog will shown and the exception will be shown after downloading.

The problem may at DownloadUpdateDialog.cs Line 110~124(ver 1.7.6)

Line 110: variable 'fileName' assigned with EMPTY string. Then, Line 124: File.Move(_tempFile,tempPath). parameter1 _tempFile is a full path filename. Parameter 2 tempPath link to the same path without any filename. It moves a file to its current path!