If you're an individual you don't have to save your bills so you don't need the viewer to look at them.
If you're a company, we remind you that you have a legal obligation to save your fiscally binding bills (Order of the Ministry of Finance 3134/2002 (Spanish National Gazette of 13 December 2002). The viewer allows you to open the fiscally valid bills filed on your computer and allows you to view them like paper bills.
If you always access your bills from Online Office, you'll never need the viewer to see them.
The viewer provided by Endesa is free and meets all technical and computer security requirements.