vMotion migration error when migrating between a host using Intel Xeon Processor 56xx series or 36xx series

vMotion fails between hosts using Intel Xeon 56xx or 36xx series processors to hosts using either Intel Xeon Processor 34xx series or Intel Core i3/i5 processors.

RESOLUTION
To resolve this issue, install this patch based on the product you are using:

• ESX 3.5
  VMware ESX 3.5, Patch ESX350-201006401-SG: Updates VMkernel, VMware Tools, hostd, VMX, VMnix (1022899)
• ESXi 3.5
  VMware ESXi 3.5, Patch ESXe350-201006401-I-SG: Updates firmware (1020052)

For more information on modifying CPU masks, see section Modifying Default Mask for Intel CPUs in VMotion CPU Compatibility - Migrations Prevented Due to CPU Mismatch - How to Override Masks (1993)

MORE INFO
http://kb.vmware.com/kb/1021023