Internal Error: Sub-system: DEV, File: /quartus/ddb/dev/dev_basic_info.cpp, Line: 606 - Internal Error: Sub-system: DEV, File: /quartus/ddb/dev/dev_basic_info.cpp, Line: 606 Description Due to a problem in the Quartus® II software version 12.1 and earlier, you may see this internal error when synthesizing a design targeting a Cyclone® V device with Physical Synthesis enabled and the Arria® V device libraries are not installed. Resolution To work around this problem, install the Arria V device libraries or disable Physical Synthesis. This problem is fixed beginning with the Quartus II software version 12.1 SP1. Related Articles Internal Error: Sub-system: DEV, File: /quartus/ddb/dev//dev_basic_info.cpp, Line: 606 Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['FPGA Dev Tools Quartus II Software'] 12.1.1 12.0 ['Cyclone® V E FPGA', 'Cyclone® V GT FPGA', 'Cyclone® V GX FPGA', 'Cyclone® V SE FPGA', 'Cyclone® V ST FPGA', 'Cyclone® V SX FPGA'] ['novalue'] ['novalue'] ['novalue']