Projects and templates have been moved from SDL folders after installing the Dropbox app

Similar questions about "disappearing files" have been asked before. I am wondering if my own is related to installing Dropbox, which has created its own folder "Dropbox" and copied all the contents of my PC (including all SDL folders) to that location. Each folder now has a green tick beside it. This means that I am back to "Project 1" on my Studio 2019, and templates are not automatically visible.

It is not strictly an SDL-related issue, but has anyone else got any experience with this? It could possibly be OneDrive-related too ... 

If it is Dropbox, and I delete the app, will the files disappear or be relocated back to original position  .. unlikely ??