If your having an issue with your virtual disk it is worth trying the following:

1. Open a Terminal window
2. /Library/Application Support/VMware Fusion/vmware-vdiskmanager -R /Users/(USERNAME_HERE or Directory where VM installed)/Virtual Machines.localized/Windows Vista.vmwarevm/Windows Vista.vmdk

If this fails with a message like ‘FILE: FileIO_Lock on ‘/Users/Shared/Virtual Machines.localized/Windows Vista.vmwarevm/Windows Vista.vmdk’ failed: Lock timed out’ then:

1. cd /Users/(USERNAME_HERE or Directory where VM installed)/Virtual Machines.localized/Windows Vista.vmwarevm/Windows Vista.vmem.lck/
2. rm * and files here
3. cd /Users/(USERNAME_HERE or Directory where VM installed)/Virtual Machines.localized/Windows Vista.vmwarevm/Windows Vista.vmx.lck/
4. rm * and files here
5. /Library/Application Support/VMware Fusion/vmware-vdiskmanager -R /Users/(USERNAME_HERE or Directory where VM installed)/Virtual Machines.localized/Windows Vista.vmwarevm/Windows Vista.vmdk

now all should be fine.