I just re-installed 11.1sp2 and opened my qsys project and now I get the "PLL cannot be synthesized" error. It appears to be a bug because it says this for all DDR2 ALTMEMFPHY configurations. No setting seems to make it go away. (I've seen a similar megawizzard bug but the workaround for megawizzard doesn't seem to apply here.) Any experience with this???Greg
Yeah, I'm sure they would. Unfortunately 12.1 seems to be giving people even more misery than 11.1. I'm re-installing from the web instead of an install file - the only difference between the last install and the previous one.