To elaborate a bit on Cameron's point... System 6 requires 24 bit addressing on the host machine. The first Macs were based on the 68000 which only has 24 address bits. When they added the Mac II and SE/30 to the line-up they switched to the 68020 and 68030 which have 32 address bits, but the OS was still operating in a 24 bit address space. So, in order to run System 6 you need hardware which can translate to 24 bit addresses. Apple included the feature of a choice of 24 bit or 32 bit addressing modes in early Macs, but abandoned it somewhere in the middle of the Quadra (68040) line-up. So, for example, the Quadra 605 can do both 24 bit and 32 bit addressing, but the Quadra 63x family cannot. My guess is that the Quadra 650 does not include support for 24 bit addressing and neither does the performa you used. This would definitely be true of any Performa 63x, or later PowerPC Performas. So, you most likely need a ROM image from an older machine. Also, even if 24 bit addressing is supported in the emulated, ROM imaged machine, Apple dropped support for OS 6 somewhere along the way in their hardware/firmware. I suspect that regardless of the 24 bit/32 bit issue, the Q650 will not run anything earlier than some flavor of OS 7. I may be misremembering, but that's how I would bet. You may want to check a website such as everymac.com, because I believe it lists the OS's supported by each Mac model. Jeff Walther