The first time you need to open a TIF document on your Windows computer, follow the below directions to open it with Windows Photo Viewer. Then in the future when you open any TIF files on that computer, they will open automatically. 

1. Save the attachment to your computer's desktop
2. Right click on the TIF file and select Open with > and then Choose another app
   
3. In the How do you want to open this file window, select Windows Photo Viewer; at the bottom check the box for Always use this app to open tif files
   
4. Click OK, and the file will open
5. The next time you need to view a downloaded TIF file, double click on the file and it will open automatically