How to fix the error "System.IndexOutOfRangeException" occurred in system.dll was not handled in user code

I scanned the whole unit with a hope to find out at least an array that has an index greater than the maximum allowable index.

It may not even be the above. What if the array has no elements in it, and somehow you try to address array[0] and remember the array has no elements in it? What error message are you most likely going to get in this example?