I use Quartus II 15 and Cyclone V. When I try to use the Altera PLL then the Megawizard just stops and dissapears. If I try to use QSYS and instantiate the PLL here then I get two error messages:
Error: can't find package ::altera::generic_pll while executing "package require ::altera::generic_pll"
Error: An instance of Altera PLL could not be created. The component had an unexpected internal error.
Does anybody know what the reason for this is?
I'd suggest upgrading to the latest version, this error was fixed in the later versions. You may need to upgrade the IP used in the project after switching to new version.