C access violation error, but not in debug mode

I have this code:

MountedJob* new_MountedJob(Job** job){
    MountedJob* new = malloc(sizeof(MountedJob*));
    printf("ok ");
    new->job = *job;
    printf("not ok");
    new->neededTools = new->job->toolSet;
    new->baseInstance = new->job->baseInstance;
    new->cj = new->baseInstance->C - hashset_size(new->neededTools);
    hashset_new(&new->unneededTools);
    return new;
}

It is executed 10 times, each time for a Job passed as an argument. They come from a iterated list and are generated exactly the same way. At the 3rd iteration, new->job = *job; crashes with access violation error code (0xc0000005). The problem is that it works just fine in debug mode so I have no clue what the problem could be. Especially that it works for the 2 first iterations, that's unconsistent I really don't understand.

Thank you.

You are not allocating the proper size:

MountedJob* new = malloc(sizeof(MountedJob));

Otherwise, you only allocated one pointer, instead of a whole structure.