ModelSim FFT simulation returns nothing but zeros

Hi, Thanks for Nicol for the explanation on the reset. @Vasilchenko, You can try the reset as recommended by Nicol. For your information, you can also generate the FFT example design (simulation) from the FFT IP -> Generate -> Generate Example Design. You can then run the simulation for the example design and cross check with yours to see if can spot any anomaly. Please let me know if there is any concern. Thank you. Best regards, Chee Pin