Hello,
Currently, there is no UI in application, which allows to reset user settings to defaults. This is something that our application framework team is considering for future release.
Here is a workaround to achieve this:
Browse to the following location on your machine
%localappdata%\ESRI\
- Inside that folder, you will find a folder named similar to this:
\ArcGISPro.exe_Url_1jclabdb3g2held3u2vfbbtsyiwtjlkq\
There should be subfolder folder there called:
\11.0.0.0\
There will you find file: user.config
Once you delete this file, application will re-create it upon next start. List of recent project should now be empty.
Max