I seem to keep having the same issue now, even after uninstalling Ryder Editor and restarting Unity Editor.

To reproduce this:
- download this project
- notice the message in the console: The editor layout could not be fully loaded, this can happen when the layout contains EditorWindows not available in this project
UnityEditor.WindowLayout:LoadDefaultWindowPreferences()

Alternatively (does not always happen):
- start a new project
- uninstall Ryder Editor
- open the Project Settings Window and notice it's there
- close the window
- install Ryder Editor 1.0.8
- try to open the project settings window again
- notice that it won't open

Cannot reproduce in 2019.2.0b9 or 2019.3.0a8
reproducible in 2019.3.0a9

WORKAROUND: reset the layout of the editor to default to get the window to appear again.