Hi Nilam,

I did some search based on the mentioned context and found some of the pointers releated to it. 

• The file.type attribute is returning blank in case of .msg file upload
•  The  issue/problem that the browser doesn't return correct mime-type for outlook-msg-files. Instead of application/vnd.ms-outlook the type-property of File shows an empty string. 

Reference links:

https://stackoverflow.com/questions/43915869/file-with-msg-extension-not-downloading

https://stackoverflow.com/questions/56137532/what-do-you-do-when-angularjs-fileuploader-returns-nothing-for-file-type

https://stackoverflow.com/questions/55687631/which-mime-type-can-i-use-for-msg-file-using-file-object

I could suggest you a work-around i.e. Using JavaScript, you can get the uploaded File type, referring to the file extesnion as mentioned-below.

JavaScript Snippet:

var control = document.querySelector("#" + $parameters.UploadWidgetId + " > input");

if (window.FileReader && window.Blob) {
    // All the File APIs are supported.
    
    control.addEventListener("change", function(event) {
    // When the control has changed, there are new files
    
        var files = control.files;
        var i = 0, fileType = "";
        
        if (files[i].name !== null && files[i].name !== undefined && files[i].name.endsWith(".msg")) {
                fileType = "application/vnd.ms-outlook";
        }
        
         $actions.SetFileInfo(files[i].type || fileType, files[i].size);
    }, false);
} else {
    // File and Blob are not supported
}

See this sample screen UploadWidget_MSG Demo

Refer to the attached .oml file

Hope this helps you!

Kind regards,

Benjith Sam