I actually found that the best way to do this was to complete either of the following instructions below. Note that this was with a Form that was owned by/within a Teams group:
- When you create your form, do so from the appropriate Teams Group Channel. The form Excel file location will, by default, be in that channel's folder, which is typically a sub-folder of your Teams Group Channel.
- If you already have a form created:
a. Identify what file is currently associated with your Form's responses (you can do this by opening the Form Responses, then looking at the path of the document near the top left side of the screen. Open the Excel file in Sharepoint Online, not in your Desktop app).
b. Open Teams and "Teams" from the left panel, then navigate to your Team that owns the form, and finally select the "Files" tab.
c. Navigate to where the Form's Excel file is located (identified in step a) using the *Teams file browser*. Once identified, click the 3-dot button and click "Move To". Select the folder you'd like to move it to, and click the checkmark to confirm the operation.
For whatever reason, if you move the excel file with anything other than Teams, Microsoft Forms cannot track the new path of said file and thus cannot re-associate the XLSX file with the form. When done using Teams, the form information is updated on the back end and links to the file's new location.
I just tested this myself and it works without a hitch!