Converting Excel workbooks to new .xlsx max

It's well know that the old format for Excel spreadsheets (with the extension .xls) for Excel 1997-2003 is 65,536 rows, and the row maximum in later versions is 1,048,576 rows. Many document productions still contain many Excel files in the older format. When you're processing a lot of data you'll want to convert the older Excel files to the new .xlsx format. If you try to accumulate a lot of data on single worksheet you may get an error message like this:

The obvious solution is to save the file in Excel 2010 or Excel 2016 to a file with the new .xlsx.

If you try to add data that goes beyond 65,536 rows immediately, you'll get the same error message. Try saving and then closing the file. This should cause the worksheet row maximum to update. Before the Excel file is closed it may still be in compatibility mode.