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 Troubleshooting a virtual machine that is unable to power on

==================Symptoms=====================

A virtual machine hosted on an ESX/ESXi host cannot be powered on

The virtual machine power on task fails

The virtual machine does not turn on.

====================Causes:========================

There are multiple potential causes for not being able to power on VMs:

Problems with file locks

VM file corruption

VM snapshot problems

VM guest OS problems

VM configuration problems

ESXi OS problems

vCenter OS problems

Storage Array/Datastore problems

Network problems

=================================================

1- VM may be configured to reserve physical memory on the host.

2-VM does not power on when there is high CPU reservation.

3-The virtual machine may be starting in a VMware High Availability cluster with strict admission control enabled, and there are insufficient resources to guarantee failover for all virtual machines.

4-A file required for starting the virtual machine, such as a virtual disk or swap file, may be unavailable or missing. For more information.

5-The virtual machine may have been previously suspended and making use of CPU features which are unavailable or incompatible with the CPU features available on this host.

6-VM may require another CPU feature which is unavailable on this host.

7-VMmay start, but quickly fail with an error during startup. Review the contents of the vmware.log file in the virtual machine's directory for any errors or warnings.

8-If the virtual machine does successfully power on, but the guest OS doesn't start correctly, there may be an incompatibility between the virtual hardware and drivers within the guest OS. For example, a missing SCSI driver may be required for booting.

9-If the guest OS, or a driver or application within the virtual machine experiences a problem during startup, the guest OS may become unresponsive.

10-Check the VMX file.

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