We know that problems frequently arise with spreadsheets. Usually these problems are referred to as errors and give spreadsheets a bad reputation. The aim of this series of reviews is to examine these potential problems in greater detail, using the ACBA Mapping software as the starting point for the investigation. This first review looks at a single file from the collection of excel files deriving from the collapse of the Enron Corporation . This particular file gave rise to a wide variety of interesting conundrums and offers a starting point for this series of reviews. The issues arising from this file are considered under the following headings. Interrupted column formulae Displaced formula Extended use of formulae Irrational references Unusual column data sequence The “BR New York ticker 10_01” spreadsheet comprises 18 worksheets, 17 of which are visible and have been mapped. Several of the worksheets have almost identical structure. The review below uses examples f