Apple has issued a cease and desist letter to Macfixit.com for posting a hack that let Macintosh users install a full version of the operating system using the 10.1 update CD alone.

Macfixit posted details that enabled this. These details were then swiftly removed after Apple served a cease and desist notice.

Apple said: "In this instance, information was provided by Macfixit that might contribute to the theft of Mac OS X software."

In its defence, Macfixit claims its posting helped resolve a technical issue. Upgrading using the Mac OS X 10.1 disc stops users reverting back to 10.1 after installing the 10.1.1 upgrade, according to Macfixit.

Macfixit said: "Although we believe the information provides a legitimate method for dealing with certain troubleshooting issues and that we were not advocating anything illegal, we understand Apple's concern and have thus co-operated."

Mac OS X 10.1 costs £99.