I've disabled Upload and manage files, but they're still enabled for a user

[AndrewL41]

I've added a user to a subscription. I've denied ALL roles apart from managing email accounts. Yet when I login as the user, they can also upload and manage files. I thought it might be that I'm logged in as administrator in another browser window, so I ensure I logged out. In fact I tried this on a separate browser altogether (Chrome, not my usual Firefox) and still when I logged in as the user, I could upload/manage files. I've explicitly stated "Denied" next to the "Upload and manage files?" option for this user, yet they remain Granted no matter what I do. How can I disable this? I don't want any of my users to have this facility.

Running Plesk 10.4.4 for Windows (OS = Windows Server 2008 R2)