I tried to migrate and clone some of the VM’s on my Test and Development cluster and I got very, very strange error message during validation:
Virtual machine has 256 megabytes of memory, which is larger than maximum 0 megabytes supported by datastore
Really ?! 
datastore validation error
vSphere ESXi 5.1.1 build 1157734 with vCenter 1123966. I tried to find something by googling but with no luck and by coincident I noticed that one of my colleagues made changes on that cluster. What he changed was host advance settings – Config.HostAgent.log.level (a debug log level) from default (verbose) to trivia . What is the relation between clone of VM and change log level on ESXi host – remain mystery. I changed back log level to verbose and problem disappeared.
ESXi host advance settings
