Under Advanced Settings chose Export Templates. Then click the Create an Export Template button.
This should give you the option to name the export and modify the exported fields. After giving the template a name, like "Product Export All Fields", click the Save and Exit button at the bottom.
You should now see a list that includes the export template you just created. From the dropdown beside your new template choose the Export Products option:
In the next window verify that your template and the "Export to Microsoft Excel (CSV)" options are chosen and click Continue.
Save the CSV to your computer and send it to us or upload it without opening it and re-saving it. If you must modify the file please see this article to avoid formatting issues.