IE cannot download MSG files

Modify the attributes of IIS to enable the restriction.

IIS -- website properties -- HTTP header -- MIME type -- New -- MIME type  
Extension. msg  
Mime application/octet-stream  


The MIME type is used to set a file extension. Program When the file with the extension is accessed, the browser automatically opens the file with the specified application. It is used to specify custom client file names and open media files.  
The following lists the MIME types of commonly used files: 

Mime-types (MIME type) dateiendung (Extension) Bedeutung  
Application/MSExcel *. xls *. xla Microsoft Excel dateien  
Application/mshelp *. HLP *. chm Microsoft Windows Hilfe dateien  
Application/mspowerpoint *. ppt *. PPZ *. PPS *. Pot Microsoft PowerPoint dateien  
Application/MSWord *. Doc *. Dot Microsoft Word dateien 
Application/octet-stream  
*. EXE exe  
Application/pdf *. pdf Adobe PDF-dateien  
Application/postscript *. ai *. EPS *. PS Adobe postscript-dateien  
Application/RTF *. rtf Microsoft RTF-dateien  
Application/X-httpd-PHP *. php *. phtml PHP-dateien  
Application/X-JavaScript *. js serverseitige JavaScript-dateien  
Application/X-Shockwave-flash *. SWF *. Cab flash Shockwave-dateien  
Application/zip *. zip-archivdateien  
Audio/basic *. Au *. snd sound-dateien  
Audio/MPEG *. MP3 MPEG-dateien 
Audio/X-Midi *. Mid *. MIDI midi-dateien  
Audio/X-mPEG *. MP2 MPEG-dateien  
Audio/X-WAV *. wav-dateien  
Image/GIF *. gif GIF-dateien  
Image/JPEG *. JPEG *. jpg *. jpe JPEG-dateien  
Image/X-windowdump *. xwd X-Windows dump 
Text/CSS *. CSS stylesheet-dateien  
Text/html *. htm *. html *. shtml-dateien  
Text/JavaScript *. js JavaScript-dateien  
Text/plain *. txt Reine textdateien  
Video/MPEG *. MpEG *. mpg *. mpe mpeg-dateien  
Video/vnd. Rn-realvideo *. rmvb realplay-dateien  
Video/QuickTime *. QT *. mov QuickTime-dateien  
Video/vnd. Vivo * Viv *. Vivo-dateien