In order to get box.com to work on my computer, I had to enable TLS 1.0, 1.1, and 1.2 in Internet Explorer, even though I almost never use IE.
I had turned off all three versions of TLS on security grounds. As a result, I kept getting an error message when I tried to log into Box Sync on my computer (“Cannot connect”).
Box.com help desk’s explanation for the requirement — amazingly — is that SSL 3.0 is not secure so they don’t use it. It’s true there have been issues with SSL 3.0, but TLS, as I understand it, has the same issues plus much worse. [UPDATE: Dan Riley explains why I have it all backwards in the comments.]
On the positive side, I only figured out the source of the problem thanks to efficient and friendly work from ‘Ashley’ at the box.com help desk, so they are doing something right.