I wrote: The easiest way is to boot while holding down the Shift key. Depress it when you hear the chime and then you can let it up when you see the rotating clock thingy start up under the Apple (is there an official name for that?). This will do a Safe Boot, which is the equivalent of what Wayne is referring to. Now I correct myself: Safe Boot isn't the equivalent of fsck, but one function that happens during Safe Boot is. That is the invisible running of First Aid test and repair during start up. Brian Conner