Hi! Having a similar issue that I've been trying to solve with no positive results so far. During my field work I manually copied and pasted all my finalized ODK forms from my phone to a local folder on my PC, then deleted the originals on the phone to clear everything for the next day. Now it doesn't seem to work to load these files into briefcase from the local folders. I get error messengers saying:
"Not an ODK collect directory (did not find both the forms and instances child directories).
Anyone who successfully have been able to convert the XML files to CSV using any other conversion application?
Does your directory contain both a forms/ folder and an instances/ folder? Briefcase needs to know about your form's structure from the form XML so that it can export the data. If you've only pulled the submissions, put those in an instances directory and then create a forms directory with just the form XML in it. Then try to import the folder that contains those two into Briefcase.
If that doesn't work for you, please fill out @yanokwa's template!