In case you still have ESX 4.0 in your enterprise and update to U3 failed with following error: DependencyError: Requested VIB rpm_vmware-esx-vmkernel64 conflicts with the host and in /var/log/vmware/esxupdate.log can be found below error message:

ERROR:  esxupdate: An esxupdate error exception was caught:
Traceback (most recent call last):
  File "/usr/sbin/esxupdate", line 242, in ?
    cmd.Run()
  File "/usr/lib/vmware/python2.4/site-packages/vmware/esx4update/cmdline.py", line 357, in Run
    deps = solver.Resolve()
  File "/usr/lib/vmware/python2.4/site-packages/vmware/esx4update/depsolver.py", line 453, in Resolve
    raise errors.DependencyError(problems)
DependencyError: Requested VIB rpm_vmware-esx-vmkernel64_4.0.0-3.22.398348@i386 conflicts with the host

You have follow procedure from VMware KB1026752

Error is related with Cisco Nexus package which is installed on ESX but not used.