Chrome has all kinds of issues since v45 was released.
I received the same error message the other day downloading an item.
I figured it had to do with Chrome’s new packed security features.
Chrome also has a lot of issues with WordPress dashboards too.
Though I must also include, I’ve only see that issue happen on a few downloads. It doesn’t seem to happen on them all but only a few. I too would be interested in knowing what is causing this and how to resolve it.