Comment 6 for bug 1437083

I confirmed this as well.

Test prodedure:

1. Clean Mahara install
2. Go to Content -> Files
3. Upload a file into the top level of your files area
4. Click "Download folder content as a zip file"
5. Try to open it with Windows' built-in zip handler (i.e. tell the browser to open it, or right-click and select "Extract all")

Expected result: The zip file should unzip with the single file in it
Actual result: The zip file opens up and appears empty, or you get an "Invalid file" message

A few more details:
- The top-level zip file worked fine in Linux, and WinRar
- The built-in Windows zip extractor works fine for other Mahara folders downloaded as zip. It's only the top-level one that causes problems.