I have been working on a file with several worksheets. Each worksheet was
only about 15 columns wide by 50 lines long. Somehow, before the most recent
save, the size of the file went from 3MB to 12MB. No new columns or rows
were added from the previous save. The only thing I have noticed that has
changed is that when I press the Ctrl and End keys, I am taken to the cell
AM1566 in each worksheet. There is no data in any cells beyond Column O, Row
50.

I have tried deleting all rows and columns out to AM1566 except for those I
am using but this did not fix the problem.