diff --git a/source/Frame.cpp b/source/Frame.cpp
index d3f04f4d..338d6e23 100644
--- a/source/Frame.cpp
+++ b/source/Frame.cpp
@@ -1815,6 +1815,16 @@ static void ProcessButtonClick(int button, bool bFromButtonUI /*=false*/)
         TCHAR filename[MAX_PATH];
         _tcscpy(filename,g_sProgramDir);
         _tcscat(filename,TEXT("APPLEWIN.CHM"));
+
+		// (GH#437) For any internet downloaded AppleWin.chm files (stored on an NTFS drive) there may be an Alt Data Stream containing a Zone Identifier
+		// - try to delete it, otherwise the content won't be displayed unless it's unblock (via File Properties)
+		{
+			TCHAR filename_with_zone_identifier[MAX_PATH];
+			_tcscpy(filename_with_zone_identifier,filename);
+			_tcscat(filename_with_zone_identifier,TEXT(":Zone.Identifier"));
+			DeleteFile(filename_with_zone_identifier);
+		}
+
         HtmlHelp(g_hFrameWindow,filename,HH_DISPLAY_TOC,0);
         helpquit = 1;
       }