SYMPTOM:
New attributes, facts, hierarchies, transformations, partitions, and logical tables cannot be created because they are missing from the menu. Navigate to File > New or right-click > New, all the objects are missing from the menu.
The menu should look like this:

But the menu will be missing objects and will look like this:

CAUSE:
This is because Architect is open and these six schema objects cannot be created while the architecture is being modified.
ACTION:
Close Architect and the objects will reappear.