When attempting to migrate a virtual machine to another host in the same cluster, the error message, "Select a valid compute resource" returns. What could cause this error?

VMware Tools affects in-guest performance features and quiescing but is not a vMotion prerequisite and would not trigger a compute resource validation error.

vMotion requires that both the source and destination hosts share access to the same datastore so the VM's disk files remain accessible during migration. If the destination host cannot see the datastore, vCenter marks it as an invalid compute resource and blocks the migration.

An ISO attached from a local datastore can block vMotion, but the resulting error identifies the CD/DVD device as the problem, not an invalid compute resource.

Mismatched ESXi versions can cause CPU compatibility errors enforced by EVC settings, but those produce a CPU incompatibility message rather than the compute resource error described.