My laptop is usually left online at home during the day but unused. My ISP has been warning me about excess data usage so I installed Glasswire to try to determine what is consuming so much data. This afternoon Dropbox used 2.4GB of data (mostly downloading) when no one was using the computer! What can be causing this and how can it be stopped or controlled?
Usually when particular machine is used (especially while files in Dropbox directory are changing) the network upload traffic is impacted mostly, not the download one! When something changes on cloud, outside your machnine (i.e. you are changind/adding Dropbox files on other device, for example), then changes have to take effect on the machine and needed information have to be downloaded (i.e. download traffic).
The most simple thing to limit your network traffic is turn Dropbox application off while you don't use particular machine and turn it on when you are going to use. So, only last file(s) state will be downloaded, not every one change you seems do on every one other devices. Disadvantage would be that some time may be need for all files to be updated to the actual state (you have to take this in mind).