Why do I get an error when trying to add an Avalon ALTPLL component in Qsys? - Why do I get an error when trying to add an Avalon ALTPLL component in Qsys? Description You might get an error, when trying to add an Avalon ALTPLL component in Quartus ® II 12.0 Qsys system, using following steps. 1. Open up Qsys 2. Add an Avalon ALTPLL 4. Edit its properties, then click "Finish" After clicking “Finish”, you may see the Error, along with related messages: Error: DLL ("altpll_avalon") not found child process exited abnormally This is caused by a bug associated with Quartus II Linux 64-bit implementation. Resolution On a Linux machine, you can use Quartus II 12.0 (32-bit), instead of Quartus II 12.0 (64-bit) to work around this issue. 32-bit version: <install folder>/altera/12.0/quartus/bin/quartus.exe 64-bit version: <install folder>/altera/12.0/quartus/bin64/quartus.exe You can also use Quartus II 12.0 PC version (either 32 or 64-bit implementation). This issue is going to be fixed in future Quartus II software version. Custom Fields values: ['novalue'] Troubleshooting novalue False ['novalue'] ['novalue'] novalue novalue ['Programmable Logic Devices'] ['novalue'] ['novalue'] ['novalue']