Error: DLL ("altpll_avalon") not found child process exited abnormally - Error: DLL ("altpll_avalon") not found child process exited abnormally Description Due to a problem in the Quartus® II software version 12.0 SP2 and earlier, you may see this error, when generating your Qsys system containing an Avalon ALTPLL. This problem occurs when generating Qsys systems on 64-bit Linux platforms. Resolution You can use one of the following solutions to resolve this issue. 1 . Generate your Qsys system using Quartus II Windows 32-bit Linux system or a PC. --Or-- 2. To use Quartus II Linux 64-bit software, take the following steps: · Locate the sopc_mwizc.tcl file at the following Quartus II installation directory path. {rootdir}/12.1/ip/altera/sopc_builder_ip/altera_avalon_mega_common/sopc_mwizc.tcl · Around line 894, delete the following line : set cbx_cmd "clearbox device_family= CBX_FILE= -f " · Replace the above line with following code # construct the path to the 32-bit version of clearbox, # to match the presence of 32-bit shared libraries being # present in the LD_LIBRARY_PATH. set qrootdir $::env(QUARTUS_ROOTDIR) set os_platform $::tcl_platform(os) if { [string equal -nocase -length 3 "lin"] } { set bindir "linux" } else { set bindir "bin" } set cbx_cmd "//clearbox device_family= CBX_FILE= -f " · Close and re-start Quartus II (if already open). Try Qsys generation . This issue is fixed beginning with the Quartus II software version 12.1. Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['FPGA Dev Tools Quartus II Software'] 12.1 12.0 ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']