I'm quite sure the CPU emulator used in BasilikII doesn't support MMU operations. So it's not going to work with virtual memory. Period. (Technically I think it stubs out a few of the memory remapping capabilities because those are needed to boot MacOS on any CPU after the 68000, but it's entirely missing the paging functionality needed for VM.) Thus I'd suggest simply not enabling virtual memory. On any modern computer you should be able to assign 128MB or more of real RAM to BasiliskII, which is more than enough for any 68k software. Your native OS can probably handle demand paging the BasiliskII process, should it be necessary, better than Apple virtual memory kludge can swap on the real thing.