Recently while working on a project to import data from an Excel worksheet using SSIS, I realized that sometimes the SSIS Package failed even though when there were no changes in the structure/schema of the Excel worksheet. I investigated it and I noticed that the SSIS Package succeeded for some set of files, but for others it failed. I found that the structure/schema of the worksheet from both these sets of Excel files were the same, the data was the only difference. How come just changing the data can make an SSIS Package fail? What actually causes this failure? What can we do to fix it?