Linux user from Canada here. I ran into the same problem, and your post came up in a Google search. In my case, the problem was my VMs are in an HPFS partition so I can share them with VMWare Player for Windows. It looks like Linux doesn’t like mmap’ping from HPFS partitions, because VMware player for Linux works just fine without mainMem.useNamedFile=FALSE if the VMs are on an ext2 partition.