Non-previewable attachments can be opened in other apps through two methods:

Method 1

1. From the Attachment Viewer, click on the file you would like to open.
2. In the top ribbon, click the More icon and select Open with Other Apps.
3. Select the app you would like to use to open the file.
   
   
   

Method 2

1. Click on the file to open and select Download.
2. Name the file and choose the download location.
3. Click Open from the pop-up that says "Download Completed" in the top right corner.
4. Alternatively, go to the download location and open the downloaded file.