Description
You may see this error message when trying to create timing constraints in a Synopsys Design Constraints (.sdc) file in the Quartus® II GUI. This error may occur when you click Insert a Constraint and search for nodes using the Node Finder.
Resolution
Timing constraint nodes can be found only after the timing netlist has been created. Open the TimeQuest timing analyzer window and create the timing netlist. Then, you can use the Node Finder to create timing constraints in your .sdc file.