ESX

Backup team complaining of RC-156 errors
Warning: This is an issue with Backups failing on VMware Virtual machines due to VMware Tools issues.
Backup team (Symantec Backup) may send us a ticket for a Symantec Netbackup RC-156 error. This error is related to VMware Consolidated Backup (VCB) where a VM Image is not obtainable to be backed up by Veritas Backup software.
Actions:
(a) Check if VMware Tools is running on the server
VMware Tools is an agent which is installed on a guest VM for the following benefits:
- Device drivers - Manual connection and disconnection of some devices while powered on - Improved mouse - Memory management - Support for quiescing a file system - Time synchronization - Ability to gracefully shut down virtual machine
If VMware Tools is not running, it would appear as follows:

If VMware Tools is running, it would appear as follows:

If the VMware Tools is not running (or Out of Date):
(b) Check for hung snapshots of the VM from the Virtual Centre (VC)
Check on the VM's Snapshot Manager and Tasks & Events section if there are any hung / failed VM snapshots. VCB snapshots have the name _VCB-BACKUP_. Remove the hung / failed snapshots.
Inform Backup team to re-run their failed backups.

VMware - Checking on License Server
How to check if the License Server is running?
Login (Remote Desktop) to the Virtual Centre server. Go to Start Menu> Run> services.msc to open up the Services Window
Ensure that the service "VMware License Server" is up and running. If it is not running, start them manually.
Go to Start Menu> All Programs> VMware> VMware License Server> VMware License Server Tools to open up the License Manager
Go to the "Server Status" tab and click on "Perform Status Enquiry". Ensure that the License Sever is up from this query
There may be situations where the License server is not responding or will not start. Under these circumstances, go to the Start / Stop / Reread tab and re-read the license file. Otherwise, try to stop and start the license server.