You saved my life. I opened MS in 32-bit and rescanned my AU manager- and it worked! Once I created a patch for Ivory and saved my concert, I re-opened MS in 64-bit and it worked like a charm. I also checked out Synthogy/s site and found a download for a 64-bit version of the Ivory AU. I'll download that and it seems you have solved my problem completely!!!! THANK YOU!