File not found is a research project that investigates the long-term reliability and stability of our digital networks. As technology is changing at a faster pace than ever the compatibility between the container to store information and the connecting systems is continuously at stake. As a consequence, we feel that our digital existence is only temporary. File not found looks at the ephemerality of the url and investigates experimental ways to materialize it in our analog environment. The first approach of a series of events is a sound performance that “infects” the human habitat through the sonification of malicious URLs. Virtual content is exploited ‘in real life’, contained in one space, sound and the audience merge into one sonic event. Banned from the Internet, the malicious urls are bouncing randomly against the walls of the space. They are no longer dead in the immaterial matter called the cloud, but as they regenerate themselves they become part of reality, they embrace the audience while creating in them a sense of total confusion.The performance is documented in a collection of printed books which are independent of digital archiving technology. Each book uses the page as surface for infection; the urls find back their materiality through a process of infection.