Internal Error: Sub-system: RTM, File: /quartus/tsm/rtm/rtm_tdb_hipi_utils.cpp, Line: 671 - Internal Error: Sub-system: RTM, File: /quartus/tsm/rtm/rtm_tdb_hipi_utils.cpp, Line: 671 Description Due to a problem in the Quartus® Prime Pro Edition Software version 18.1, this error message may be seen while the compile flow is running the Fitter Plan stage. Resolution To work around this problem, turn off the early Fitter Retime step that is run by the Fitter Plan stage adding the following assignment into the Quartus Settings File ( .qsf ): set_global_assignment -name FITTER_EARLY_RETIMING OFF This problem is scheduled to be fixed in a future release of the Quartus® Prime Pro Edition Software. Custom Fields values: ['novalue'] Troubleshooting 2206125718; False ['novalue'] ['FPGA Dev Tools Quartus® Prime Software Pro'] 18.1.1 18.1 ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']