Is there anything unusual about the files at all? As I'm sure you can imagine this is a fairly common activity (I routinely upload files of more than 1 MB into the Document Library without any issue). Do you have any issues creating content in any other way (i.e. using the "Create Content" menu"). Does it occur on both "drag-and-drop" uploads as well as the standard upload button (that shows the file picker)?
I've had a scan through the JIRA issues related to upload and couldn't see anything that indicated we had a problem on a Community release that was subsequently fixed and I'm fairly confident that if our customers couldn't upload files then we'd have heard about it.
This isn't to suggest that the problem that you're experiencing isn't occurring, just that maybe there is some environmental issue impacting you. Maybe something specific about either the file or the installation (Windows permissions for example?).
