VUM cannot scan some hosts

[hamilton00]

When scanning a cluster, a few of the hosts in the cluster fail to scan with the following error:

VMware vSphere Update manager had an unknown error. Check the events and log files for details.

     Task: Scan entity

     Scanning object esx.domain.com

     Could not scan esx.domain.com

Any ideas?

[a_nut_in · Accepted solution]

What version of esx/esxi?

What version of VC/UM?

What do you have in terms of errors in the esxupdate.log file available at /var/log or /var/log/vmware/ depending on the host versions you are running?

[hamilton00]

vsphere 5.1.

i rebooted the affected hosts then the scan was successful. however now i notice i can't remediate because alot of my VM's boot from an ISO. even if you check the "disable any removable media devices connected to the virtual machines on the host" option it still does not allow the remediation to work. It worked before vSphere5.1. 5.1 has nothing but bugs all over... just add it to the list of 5.1 problems.