Here you can set the Project Folder for your local SI Projects.
The Projects Folder form allows to browse and change your local Project Folder if desired.
This setting is for your local Project Folder, not your server Project Folder. Do NOT change this path to be the same as your server Project Folder. We recommend leaving this folder on your local machine vs. changing to a folder on your network as this will decrease performance. The default path is C:\Users\username\Documents\SI Projects
Also, this must not be set to a shared folder or a redirected folder. If you redirect your user's "My Documents" folders to another machine, consider changing this path to be C:\SI Projects.
Seriously, you should listen to us on this one.
If you upgraded from a previous version of SI, say SI 2018, then this default path will be: C:\Users\username\Documents\SI 2018 Projects