** Error: ../top_level_filename.vho: (vcom-1136) Unknown identifier "FOURTEENNM_CT1". - ** Error: ../top_level_filename.vho: (vcom-1136) Unknown identifier "FOURTEENNM_CT1". Description Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 21.1, you might see this error when running a post-fit or post-synthesis gate-level VHDL (.vho) simulation that includes high-speed transceivers. Resolution To work around this problem, edit the .vho file to ensure that the following library and package declarations are in place. For Intel® Stratix® 10 devices LIBRARY FOURTEENNM; LIBRARY FOURTEENNM_HSSI_ALL; LIBRARY IEEE; USE FOURTEENNM.FOURTEENNM_COMPONENTS.ALL; USE FOURTEENNM_HSSI_ALL.CT1_HSSI_COMPONENTS.ALL; USE FOURTEENNM_HSSI_ALL.CTP_HSSI_COMPONENTS.ALL; USE FOURTEENNM_HSSI_ALL.CT1_HIP_COMPONENTS.ALL; USE IEEE.STD_LOGIC_1164.ALL; For Intel Agilex® devices LIBRARY TENNM; LIBRARY TENNM_HSSI_ALL; LIBRARY IEEE; USE TENNM.TENNM_COMPONENTS.ALL; USE TENNM_HSSI_ALL.CT1_HSSI_COMPONENTS.ALL; USE TENNM_HSSI_ALL.CTP_HSSI_COMPONENTS.ALL; USE IEEE.STD_LOGIC_1164.ALL; The above changes address the problem for the ModelSim* Intel® FPGA Edition simulator. For all other simulators, run the Intel® Quartus® Prime Software library compiler to generate and optionally run the library compilation commands compatible with the modifed .vho file. This problem is fixed starting with the Intel® Quartus® Prime Pro Edition Software version 21.2. Custom Fields values: ['novalue'] Troubleshooting 14013837528 False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Pro'] 21.2 21.1 ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']