This was Microsoft’s curious strategy to keep hackers away: 30MB of storage

Before the days of broadband internet and gigabyte-sized software, Microsoft found a surprising way to slow down software piracy—by using an old, forgotten product: Microsoft Bob. During the development of Windows XP, engineers realized that installation CDs still had about 30MB of unused space left after padding. Instead of leaving it empty, they encrypted and filled it with Bob.

Microsoft Bob returned from the dead as digital ballast

Originally designed to make Windows more friendly, Microsoft Bob featured a cartoon-style interface with a virtual assistant dog named Rover. Despite its good intentions, the project flopped and was discontinued after poor sales and high hardware demands. But years later, Microsoft Bob was reborn—not as software, but as a tool to fight piracy.

A veteran Microsoft engineer explained that they packed the CD with encrypted “dummy data”—a blob made from Bob’s floppy disk images. This forced pirates to download an extra 30MB when copying the installation CD, which at the time was a meaningful deterrent given the popularity of dial-up connections.

An odd layer of protection buried inside Windows XP

Another developer involved in the process described how he encrypted the files using multiple layers of cryptographic tools and random data, creating what he called a “Bob blob.” This blob became a unique identifier for each CD version—OEM or retail—effectively turning a discontinued product into a security feature.

Microsoft’s unusual decision to use Bob as ballast is a quirky footnote in its history. In the end, Bob may have been more useful dead than alive, helping the company slow down piracy in the early 2000s in a surprisingly creative way.