Thank you, this finally worked for me too, with a slight modification.

Running QB 2020 Desktop Premier, I upgraded to Office 365 from Office 2010. Didn't like it and uninstalled 365, reinstalled 2010. Excel Export would not work no matter what I did. Checked the registry key mentioned here - I didn't find 1.9, but I had 1.7 and 1.8. 1.7 refers to Excel 14.0, which is the version number of Office 2010, so I left it alone. 1.8 referred to Excel 15.0. I deleted that entire 1.8 key. Problem solved.