In the US, disgruntled customers often get together to sue big corporations. And this time, it's Apple 's turn.

A group of American Mac users, angry about their defective MacBooks, have teamed up to take legal action against Apple. The MacBooks turn themselves off from time to time, a phenomenon that is widely known on the web as RSS, Random Shutdown Syndrome. Thousands of MacBook users around the world have been affected.

Apple has promised to sort out the problem but the group behind the lawsuit claim that they have been without an effectively working computer for a long time. For some, the problems have continued even after contacting AppleCare for repair. The group behind the lawsuit now wants Apple to take responsibility and recall all affected MacBooks.

There are many theories as to what causes these shutdowns, but a German IT technician has found that the cable between the heat sensor and the CPU's heat sink is too short. When the MacBook is operational, the heat sink expands and comes into contact with the sensor cable melting through the cable's insulation.

Once the protective outer layers of the cable melt away, the cable touches the heat sink which causes a short circuit, resulting in an immediate shutdown.

So far Apple has solved the problem by replacing the heat sink but a considerable number of users say that the problems have arisen again after some time. The next step may be to replace the entire mainboard. Some customers have been told that Apple is developing an entirely new mainboard where the problem of short-circuiting cannot happen but Apple could not say when this would happen.

If you've been affected by these MacBook problems, get in touch with the AppleCare support centre to get the faulty parts replaced without cost. Anna Lagerkvist