The SAS^® 9.2 XLS engine creates Microsoft Excel .bak files in the same directory as the Excel workbook when you update the workbook or add multiple worksheets. A .bak file is created because a backup copy of the Excel workbook is created before the XLS engine attempts to update the existing Excel workbook. These .bak files are not deleted when the update is made.

This problem occurs in SAS 9.2 (TS2M0) and later because the XLS engine can create multiple worksheets and update worksheets in the same location.

When SAS creates a new workbook with the XLS engine, a .bak file is not created because no backup copy is required.

Currently, there is no solution or workaround for this problem.