I have a rather large Excel file, with approxmately 800,000 rows of data in it. I noticed when I save this as an Excel file, the total file size is about 44 MB. However, if I export it as a CSV file, it shoots up to about 588 MB. Similarly when I import the 44 MB Excel file into an Access database, the database winds up being 566 MB. I even tried the compact and repair option, but it made no difference to the total file size. I thought Access was supposed to be more efficient with large data, am I missing something here?