Identifying dates that are not included

I am trying to identify gaps in coverage for insurance. Even if there is a 1 day gap, I would like to identify that person in Column D by indicating "Gap in coverage".

For example, Joseph's coverage years are 7/7/11 to 7/6/12 (Row 2), 5/12/10 to 5/11/11 (Row 4), 7/7/12 to 7/6/13 (Row 5) and 5/12/09 to 5/11/10 (Row 7). Joseph has had continuous coverage except between 5/12/11 to 7/6/11. I would like Column D to indicate when the person had a lapse in coverage. Please assist with a simple formula - thanks

Not worried about being too simple but need a formula to work. I have too sort through 30,000 + rows - thanks

Sorry FDibbins, I do not want to sort the data but just want the cell to compare data from the entire column.

I figured it out. I created 2 hidden Help Column. First Column (Column H) to combine the Name and Start date (minus 1). The next Column (Column I) to combine the Name and the End Date. In the 3rd column I added =IF((H2=$I$2:$I$20), "", "Gaps in coverage")

It worked like a charm.

Thanks