Many custom libraries include the entire breakout board module (complete with terminal blocks, inductors, and potentiometers) rather than just the bare IC.
The component should appear in the results list alongside its schematic preview. Double-click to add it to your devices list. Setting Up a Test Simulation Circuit Lm2596 Proteus Library Download
Most libraries use the same symbol; just ensure your PCB layout uses the SMD footprint (e.g., DDPAK/TO-263). Many custom libraries include the entire breakout board
Double-check that the .LIB and .IDX files were placed in the correct directory. Verify if your version of Proteus uses the hidden ProgramData path. Lm2596 Proteus Library Download