There’s a previous post from 5 months ago on this topic.
I just recently bought Webroot for our small company, and I’m in the process of rolling it out to my Mac users, I have run into the same issue with Dropbox and the initial scan that the previous post talks about.
We have nearly 900 GB in our Dropbox! I tried signing out of Dropbox on my Macbook that I use for testing, to see if the initial Webroot scan would thus quickly skip or ignore files that aren’t stored locally. But the scan just attempts to open a Dropbox file (online only), and it waits several seconds to see if it will download before moving on.
From the previous post, I was hoping that enough time has gone by that an update to Webroot for Mac might have resolved this. It doesn’t appear so.