An error message is reported in the VMware Infrastructure Client
‘VMware ESX Server unrecoverable error: (vcpu-0). Could not reserve memory for vmm64. Are you sure your VM specifiEs a 64 bit guest 0S?’
This error is caused, in my case inadvertently when the 64-bit version of Solaris is installed into a 32-bit defined VMware Virtual Machine. By default the Solaris 10 installation iso comes with both 32-bit and 64-bit versions. During the installation process if it detects a 64-bit compatible platform it will install the 64-bit version unprompted. This may be a problem later if your ESX servers are not all 64-bit compatible and therefore would not be able to accept a 64-bit VM migration or if you intend to install a 32-bit version of an application such as Oracle into the OS.
If 64-bit is not a problem then edit the settings of the VM when it is powered down and select the 64-bit version as the Guest Operating System. This should now work when powered up.
To revert to the 32-bit version, first configure the Guest OS as (64-bit) see above. Power on the VM in 64-bit mode and you now need to force the Solaris OS to boot in 32-bit mode.
To do this run the following command with superuser privileges from a command line prompt within the guest Solaris VM:
Shut down the Solaris VM, edit the VM settings and then reconfigure the Guest OS as Sun Solaris 10 (32-bit). Power on the VM and both the VM and OS should be running as 32-bit regardless of the host hardware.