Another way to use the 7.2 virtual machine is to convert it and run on ESXi.  VMware provides a free downloadable converter for this.  The failure is only seen when booting the 7.2 VM on Fusion (or Workstation).  Engineers are working on a fix now.  As Peter said the upgrade process is another workaround.
Hello Isilon,  when starting the Isilon simulator 7.2 it stops with the error /ifs could not be mounted.  Is there a fix available  Regards  Heiko
Isilon Simulator 7.2 does not run : /ifs could not be mounted