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Excel has a limit to the number of rows and columns that can be used per worksheet, which is exceeded quickly with certain study/device data sets. CSV files however can hold many more rows of data than XLS, and do not have these issues. Additionally there are file size limits with Excel workbooks which are difficult to design and implement certain reports around. Formatting requirements can also cause challenges with mixing various types of transactional data (for example, laboratory reported test data and application audit records). Customers can learn more about Excel file limits from this Microsoft support article.
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