Why do I get "Fatal Error: Access Violation at" when running quartus_syn or quartus_fit?
Description Due to a problem in the Quartus® Prime Pro Edition Software versions 26.1 and earlier, and Quartus Prime Standard Edition Software versions 25.1 and earlier, compilation may terminate with a "Fatal Error: Access Violation" message during synthesis or fitting. This failure can occur intermittently, and the reported memory address may change between compilation runs. You may observe one or more of the following behaviors: Quartus® compilation fails during synthesis or fitting The failure may occur in either of the following modules: quartus_syn (during synthesis) quartus_fit (during fitting) The error message is similar to: *** Fatal Error: Access Violation at <<ADDRESS>> The reported memory address may change between runs. The fatal error is followed by a stack trace that includes one of the failure signatures listed below. CDB_SGATE_OTERM::adopt_fanouts HDB_ASGN_CONTAINER::remove_assignment LUTIL_DEVICE::get_fragment_from_subloc STA_NODE::reset_tag_heads DESIGN_HDB_ASSIGNMENT_CONVERTER::cleanup_after_conversion BSYN_RTM_FLOP::IsExpired RTM_ATOM_MGR::rip_out_simple_ff_for_bypass IRTM_FF_QUEUE::remove_ff PTI_BCM_TIMING_GRAPH::push_back_carry_hipi_clock_iterm FTM_TREE_NODE::num_sgates Stack traces may differ, even when compiling the same design. Specific Failure Signatures: Synthesis failure (quartus_syn): The crash report includes the following function call: RTL_ADDER::aggressive_adder_balancing Fitter failure (quartus_fit): The error occurs very early after the fitter starts, and the crash report includes the following function call: qhd_reread_global_assign_from_qsf Error Log Examples Stack Trace example for crashes in quartus_syn *** Fatal Error: Access Violation at 00007FFB92E2C63E Module: quartus_syn.exe Stack Trace: Quartus 0xc63d: CDB_SGATE_OTERM::adopt_fanouts + 0x2d (db_cdb_sgate) Quartus 0x117e7: RTL_ADDER::shrink_iports + 0x1f7 (SYNTH_OPT) Quartus 0x14a75: RTL_ADDER::create_binary_adder + 0x49e9 (SYNTH_OPT) Quartus 0x45910: RTL_ADDER::restrict_adder_network + 0x84a (SYNTH_OPT) Quartus 0x4f5d6: RTL_ADDER::aggressive_adder_balancing + 0x9d (SYNTH_OPT) Quartus 0x11533: RTL_SCRIPT::call_common_rtl_fns + 0x1043 (SYNTH_OPT) Quartus 0x115b5: RTL_SCRIPT::call_named_function + 0x8a2 (SYNTH_OPT) Quartus 0x3a87a: RTL_SCRIPT::process_script + 0x62c (SYNTH_OPT) Quartus 0x3a8e4: run_parallel_rtl + 0x1db4 (SYNTH_OPT) Quartus 0x8509d: SYNTH_QIS::SYNTHESIS_FLOW::run_parallel_rtl_in_helper_processes + 0x285 (synth_qis) Quartus 0x850d5: SYNTH_QIS::SYNTHESIS_FLOW::high_level_synthesis + 0x47d (synth_qis) Quartus 0x8546d: SYNTH_QIS::SYNTHESIS_FLOW::run_current_phase + 0x286 (synth_qis) Quartus 0x854d4: SYNTH_QIS::SYNTHESIS_FLOW::run_full_flow + 0x30d (synth_qis) Quartus 0x859b7: QIS_RTL_STAGE_IMPL::synthesize + 0x467 (synth_qis) Quartus 0x15b55: qis_synthesize + 0x245 (synth_qis) Quartus 0x16442: TclNRRunCallbacks + 0x62 (tcl86) Quartus 0x16f4d: TclEvalEx + 0x9ed (tcl86) Quartus 0xa6ab8: Tcl_FSEvalFileEx + 0x22b (tcl86) Quartus 0xa5136: Tcl_EvalFile + 0x36 (tcl86) Quartus 0x15246: qexe_evaluate_tcl_script + 0x4e6 (comp_qexe) Quartus 0x1143b: qexe_do_tcl + 0x46b (comp_qexe) Quartus 0x1a70e: qexe_run_tcl_option + 0x5ee (comp_qexe) Quartus 0x16451: QCU::DETAIL::initialize_qhd_and_run_qexe + 0xa1 (comp_qcu) Quartus 0x1f8e2: qcu_run_tcl_option + 0x2f2 (comp_qcu) Quartus 0x1b1ba: qexe_standard main + 0x26a (comp_qexe) Quartus 0x29eb: qexe_run + 0x3eb (comp_qexe) Quartus 0x1192p: qsyn2_main + 0x1a9p (quartus_syn) Quartus 0x1e808: msg_main_thread + 0x18 (CCL_MSG) Quartus 0x17021: msg_thread_wrapper + 0x71 (CCL_MSG) Quartus 0x1c89d: mem_thread_wrapper + 0x70 (CCL_MEM) Quartus 0x1b49d: msg_exe_main + 0x20d (CCL_MSG) Quartus 0x2b6c: __scrt_common_main_seh + 0x11c (quartus_syn) Quartus 0x2e8d6: BaseThreadInitThunk + 0x16 (KERNEL32) Quartus 0x5b3b: RtlUserThreadStart + 0x2b (ntdll) End-trace Stack Trace example for crashes in quartus_fit *** Fatal Error: Access Violation at 00007FFB8F79CFF7 Module: quartus_fit.exe Stack Trace: Quartus 0x1cff6: HDB_ASGN_CONTAINER::remove_assignment + 0x52 (DB_HDB) Quartus 0x1cf71: HDB_ASGN_CONTAINER::destroy_assignment + 0x31 (DB_HDB) Quartus 0xca69c: anonymous namespace::delete_all_global_assignments + 0x25c (comp_qhd) Quartus 0xcc344: qhd_reread_global_assign_from_qsf + 0x384 (comp_qhd) Quartus 0x51679: QHD_DATABASE_UTILS::load_design + 0x449 (comp_qhd) Quartus 0x1e1e0: FIT2_DATABASE_EXPERT_QDB::load + 0x5b0 (comp_fit2) Quartus 0x3xee: fit2_create_fitter_netlist + 0x3xee (comp_fit2) Quartus 0x16442: TclNRRunCallbacks + 0x62 (tcl86) Quartus 0x16f4d: TclEvalEx + 0x9ed (tcl86) Quartus 0xa6ab8: Tcl_FSEvalFileEx + 0x22b (tcl86) Quartus 0xa5136: Tcl_EvalFile + 0x36 (tcl86) Quartus 0x15246: qexe_evaluate_tcl_script + 0x4e6 (comp_qexe) Quartus 0x1143b: qexe_do_tcl + 0x46b (comp_qexe) Quartus 0x1a70e: qexe_run_tcl_option + 0x5ee (comp_qexe) Quartus 0x16451: QCU::DETAIL::initialize_qhd_and_run_qexe + 0xa1 (comp_qcu) Quartus 0x1f8e2: qcu_run_tcl_option + 0x2f2 (comp_qcu) Quartus 0x29eb: qexe_run + 0x3eb (comp_qexe) Quartus 0x16f2d: qfit2_main + 0x82d (quartus_fit) Quartus 0x1e808: msg_main_thread + 0x18 (CCL_MSG) Quartus 0x17021: msg_thread_wrapper + 0x71 (CCL_MSG) Quartus 0x1c89d: mem_thread_wrapper + 0x70 (CCL_MEM) Quartus 0x1b49d: msg_exe_main + 0x20d (CCL_MSG) Quartus 0x2b6c: __scrt_common_main_seh + 0x11c (quartus_fit) Quartus 0x2e8d6: BaseThreadInitThunk + 0x16 (KERNEL32) Quartus 0x5b3b: RtlUserThreadStart + 0x2b (ntdll) End-trace Resolution This problem is currently scheduled to be resolved in a future release of the Quartus Prime Pro Edition Software and the Quartus Prime Standard Edition Software. If you are using Quartus Prime Pro Edition Software version 26.1, apply the attached patch for your operating system: Download the Linux or Windows patch package for your platform. On Linux, install the patch package from the console. On Windows, run the patch executable file. Confirm the installation by opening the Quartus Prime GUI and checking the About window, or by running: quartus_sh -v If applying the patch is not possible, or if you need assistance with other Quartus Prime software versions, contact your local Altera support representative. Additional Information Affected software: Quartus Prime Pro Edition Software version 26.1 and earlier Quartus Prime Standard Edition Software version 25.1 and earlierWhy is the Avalon MM interface optimized away when using the SDI Audio Embed or SDI Audio Extract IP?
Description Due to a problem in the Quartus® Prime Pro Edition Software version 25.3 and earlier, the SDI Audio Embed IP and SDI Audio Extract IP might show incorrect behaviour when the generated IP name is audio_embed or audio_extract. In this condition, the affected output ports are left undriven and connected to the default value gnd, you will see messages similar to those shown below: Output port "reg_waitrequest" in instance "u0" of entity "audio_extract" does not have a driver. Connecting to the default value "gnd". Output port "reg_readdatavalid" in instance "u0" of entity "audio_extract" does not have a driver. Connecting to the default value "gnd". Output port "reg_readdata[0..7]" in instance "u0" of entity "audio_extract" does not have a driver. Connecting to the default value "gnd". Output port "reg_waitrequest" in instance "u1" of entity "audio_embed" does not have a driver. Connecting to the default value "gnd". Output port "reg_readdatavalid" in instance "u1" of entity "audio_embed" does not have a driver. Connecting to the default value "gnd". Output port "reg_readdata[0..7]" in instance "u1" of entity "audio_embed" does not have a driver. Connecting to the default value "gnd". Resolution To work around this problem, use a different IP name to avoid a naming that conflicts with the generated HDL module naming used by the Quartus® Prime Pro Software for the SDI Audio Embed or SDI Audio Extract IP. For example: Do not name the SDI Audio Embed IP as audio_embed. Do not name the SDI Audio Extract IP as audio_extract. Regenerate the IP after renaming it to a non-conflicting name. This problem is currently scheduled to be resolved in a future release of the Quartus ® Prime Pro Edition Software.Why does Board Support Package Editor fail to generate embedded peripheral IP drivers when generating BSP FreeRTOS project for Nios® V processor?
Description Due to a problem in the Quartus ® Prime Standard Edition Software version 24.1 and 25.1, the BSP Editor fails to generate embedded peripheral IP drivers, when it is generating BSP FreeRTOS project for Nios ® V processor. This is because the BSP Editor is not enabled to generate those drivers in FreeRTOS. Refer to Embedded Peripherals IP User Guide - Driver Support for the list of embedded peripherals with driver support. Resolution Patches are available to fix this problem for the Quartus ® Prime Standard Edition Software version 24.1 and 25.1 Linux and Windows versions. Download and install patch below. Quartus® Prime Standard Edition Software v24.1 Patch 0.01 Quartus® Prime Standard Edition Software v25.1 Patch 0.01 This problem is currently scheduled to be resolved in a future release of the Quartus ® Prime Standard Edition Software.Why are some simulation library files missing when compiling for Questasim*?
Description Due to a problem in Simulation Library Compiler in the Quartus® Prime Standard Edition Software 23.1 and later, you may see some Quartus® Simulation Library source files not included for compilation for Siemens* Questasim* Tool selection. This problem persists on both EDA Simulation Library Compiler GUI and command line versions. This problem only exists in Quartus® Prime Standard Edition and does not affect Quartus® Prime Pro Edition versions. Resolution To work around this problem, follow these steps: 1. Edit file: <QUARTUS INSTALLATION DIRECTORY>/quartus/common/tcl/internal/simlib_comp.tcl 2. Replace: set gl(primary_tool,questasim) questasim With: set gl(primary_tool,questasim) modelsim This problem is scheduled to be fixed in a future release of the Quartus® Prime Standard Edition Software.Why does the outclk of the ALTCLKCTRL IP remain enabled when using the ENA input in External Path mode?
Description Due to a problem in the Quartus® Prime Standard Edition Software version 22.1 or earlier, you might see that the output clock of the ALTCLKCTRL IP remains enabled regardless of whether the ENA input is asserted or de‑asserted when using the “External path” mode. This problem occurs because the ENA input port is not used in “External path” mode even if the “Create ‘ena’ port to enable or disable the clock network driven by this buffer” option is selected. Beginning with the Quartus® Prime Standard Edition Software version 23.1, the software will generate an error message indicating that the “Create ‘ena’ port” option is unavailable when the “External path” type is selected. Resolution To work around this problem using the ALTCLKCTRL IP with the “External path” mode: Disable the “Create ‘ena’ port to enable or disable the clock network driven by this buffer” option in the Parameter Editor. If you require clock gating, implement the gating logic external to ALTCLKCTRL (for example, gate the source clock or use an alternate supported clock‑control scheme) rather than relying on the ALTCLKCTRL ENA port in “External path” mode.Why does niosv-download return “Invalid reset option” when executing reset from debug module?
Description Due to a problem in the Ashling RiscFree IDE for Altera® software, the niosv-download returns “Invalid reset option” when executing reset from debug module for designs targeting Nios ® V processor. The affected versions are: Software version 25.2.1 (version dated 9 th May 2025, paired with Quartus® Prime Pro software version 25.1.1 and Quartus® Prime Standard software version 25.1) Software version 25.3.1 (version dated 1 st Aug 2025, paired with Quartus® Prime Pro software version 25.3.1) Software version 25.4.1 (version dated 31 st Oct 2025, paired with Quartus® Prime Pro software version 26.1) The problem is caused by Ashling GDBServer failing to execute software reset (swreset), and niosv-download is using Ashling GDBServer to communicate with the processor. Thus, this failure prompts the “Invalid reset option” message when executing “niosv-download –r". Resolution To work around this problem, use the argument “-o” to change from Ashling GDBserver to OpenOCD. $ niosv-download –r -o This problem is fixed beginning with the Ashling RiscFree IDE for Altera® Quartus® software version 26.1.1-C, which is paired with Quartus® Prime Pro software version 26.1.1. Related Articles NIOS V/m dbg_reset_out signal (Q25.1 Std, MAX10) | Altera Community - 352387Why does Quartus® Prime Standard Edition Software v24.1 hang and fail to close after using the Programmer?
Description Due to a problem in the Quartus® Prime Standard Edition Software version 24.1 and later, the Quartus® Prime Standard Edition Software might become unresponsive and fail to close after running the Quartus® Prime Programmer on Windows* 10 environments. The typical sequence that triggers the hang is: Launch the Quartus® Prime Standard Edition Software. Launch the Quartus® Prime Programmer from within the Quartus® Prime Standard Edition Software and complete programming. Close the Quartus® Prime Programmer. Attempt to close the Quartus® Prime Standard Edition Software. Result: Windows shows “Not Responding” and the application must be forcibly terminated. Resolution To work around this problem in the Quartus® Prime Standard Edition Software version 24.1, download and install the patch below: This problem is scheduled to be fixed in a future release of the Quartus® Prime Standard Edition Software.Why I can't open Early Power Estimators (EPE) tool in the latest version of Microsoft* Excel?
Description Due to the legacy design of the Early Power Estimator (EPE) worksheets, which include VBA macros, ActiveX components, and embedded DLL files, errors may occur when opening the Excel file on newer Windows platforms or when using Microsoft* Office 365, in both 32-bit and 64-bit versions. When the spreadsheet is opened, several actions occur in the background. Excel extracts the embedded DLLc files to the user's %TEMP% directory. A script then decompresses the DLLc files into standard DLL files. The script subsequently loads and executes the DLL files, which is used by the Excel macros. Why the issue occurs: To extract and execute the required DLL files, the Excel macros rely on a set of commands provided by Microsoft .NET and Microsoft Visual C++ runtime libraries, depending on the specific version of the Excel worksheet. In newer versions of Microsoft Windows and Microsoft Office 365, these runtime components are no longer bundled together by default, and some legacy functions used by older scripts have been deprecated or replaced with newer implementations. As a result, scripts designed for earlier environments may fail when attempting to call these functions. Note: In some systems, some of these are already installed automatically by other 3rd party software tools during installation. Additionally, the legacy script design does not support symbolic linking or modern handling of the user's %TEMP% directory, which can cause issues when extracting and accessing temporary files. Modern systems also enforce stricter security controls, including: ActiveX restrictions in newer versions of Microsoft Excel Trust Center policies that block code execution from untrusted locations Operating system security policies in Microsoft Windows that may prevent DLL execution from the %TEMP% directory if such restrictions are enabled As a result, if any of these conditions are triggered, users may encounter errors such as “Unable to find or load DLL files.” For example, errors may appear related to the zlib.dll file (the 32-bit or 64-bit version used depends on the installed Excel architecture). Resolution To workaround this issue PART A: Unblocking the Excel and Enable Macros/ActiveX 1. Unblock the Excel File • Right-click the EPE Excel file → Properties → Check Unblock under Security. • Click Apply → OK. 2. Enable Macros and ActiveX • Open Excel → File → Options → Trust Center → Trust Center Settings: Enable Macros. Enable ActiveX controls. Leave other settings as default (Safe Mode can remain enabled or disabled). 3. Check whether you can now open the EPE excel sheet. Else proceed to PART B. PART B: Installing the necessary Microsoft .NET and Visual C++ runtime libraries. Microsoft .NET installation Go to your Installed apps settings and find for .NET. It is recommended to have both .NET Runtime and ASP .NET installed in your system. If you already have a version installed on your machine then proceed to the next step( you only require 1 version each), otherwise refer to this location to download Download .NET 8.0 (Linux, macOS, and Windows) | .NET Example: Microsoft Visual C++ Installation As different EPE Excel sheet relies on specific Visual C++ version, you will need to install multiple versions of Visual C++ for both 32bit and 64bit. This is because even though Excel is running on 64bit, existing scripting might have dependency on 32bit functions as well. Recommendation to install C++ version for both 32 bit and 64 bit as below Latest Supported Visual C++ Redistributable Downloads Visual Studio 2017-2026 Visual Studio 2015 (in older Microsoft release, it might show as C++ V14 or 2015-2022 version) Visual Studio 2013 Visual Studio 2012 Example After installing both 32 bit and 64 bit, do restart the system and then try launching the EPE excel sheet again. In some rare occurrences, you might need to install Visual Studio C++ 2010 , Visual Studio C++ 2008 and Visual Studio C++ 2005. Do refer to PART C first as the issue might not be due to Visual C++ but symbolic link. PART C: Symbolic Link issue workaround (optional) If installing the .NET and Visual C++ runtime libraries still does not help in resolving the error opening EPE Excel, you should check whether your %TEMP% file folder is the same as what reported in the error when opening the EPE excel sheet. If the folder path are different between %TEMP% and the path reported by Excel sheet, it means that they are using symbolic link folder. In this case user should copy the .dll files generated out from the %TEMP% when they opened the excel sheet and copy it over to the Windows SySWoW folder (%windir%\SysWOW64). To access your %TEMP% folder , just type %TEMP% into your explorer and it will open your folder location (%TEMP% is set in windows environment variables) From the %TEMP% folder, there are multiple *epe* DLL files if you open different EPE excel sheets. Copy all of these .DLL files into your Windows SysWOW64 folder and try launching the EPE excel sheet again. Example, if using Cyclone® V EPE excel sheet, these are the 4 files required in red box in %TEMP% to be copied over NOTE 1: The SysWOW64 folder is selected because it is part of Windows’ default search locations when required DLL files cannot be found. Alternatively, you can add a custom directory to the Windows Environment Variables (PATH) so that Windows will also search that folder when looking for the DLL files. NOTE 2: Adding the %TEMP% folder into the system environment variables will not have any effect as latest Microsoft Windows have blocked the DLL searching mechanism to prevent search %TEMP% folder as part of the security to prevent remote execution from DLL. Additional Information If all fails, alternatively install Process Monitor from Microsoft to analyze the DLL failure/error 1. Download Process Monitor from this location Process Monitor - Sysinternals 2. Close all excel sheets that is open in Windows. 3. Launch the Process Monitor , then select Filter. Set to Process Name and EXCEL.exe and click Add. 4. After adding the filter, ensure that capturing is started 5. Then open any of the EPE excel file,and wait till you get the DLL (eg. epe_zlib_32bit.dll) error then press pause on the Process Monitor. 6. Then use Find and search for the dll error stated in the excel(eg. epe_zlib_32bit.dll) It will give you a list of things, but important is to check the details on createfile, open, close , query, those are the functions that are in the zlib dll file. Example Good case scenario where no error occurred. Fail case scenario where Windows unable to locate the DLL (due to symbolic link issue)Why I can't open Early Power Estimators (EPE) tool in the latest version of Microsoft Excel?
Description There is a compatibility issue with the current EPE tools with the latest update from Microsoft* on the Excel version 2505 and later. The update from Microsoft causes the EPE tools to stop working. Resolution There is no plan to fix this. Users need to use the Excel version before version 2505 for the EPE tools to work. There is a workaround if the user needs to use the latest Excel version, please contact Altera support and quote this ID #15018720346How to mitigate the security vulnerability in the Nios® II Command Shell utility?
Description Due to a problem in the Quartus ® Prime Standard and Lite Edition Software version 19.1 through 24.1, the Nios® II Command Shell utility included in the Quartus ® Prime Software for Windows* is vulnerable to a Current Working Directory (CWD) planting attack. The Linux* versions are not affected. Resolution To work around this problem, replace the “Nios II Command Shell.bat” Windows Batch File located in the <drive>:\<edition>\<version number>\nios2eds\, with the attached file below. This problem is fixed beginning with the Quartus® Prime Standard and Lite Edition Software version 25.1.
