we need more details.
Please attach the latest vmware.log of the VM to your next post and provide some background information.
if you are using vcenter Server - try to start directly from esxi
See the vmware.log file in the considered VM's directory ( /vmfs/volumes/datastore/vm/...) after trying to start the VM and check the related events.
We need to have more details about your problem
It could be a problem with your vCenter Server - I would try to start the VM on the host directly and check the vCenter Serer (diskusage, DBs, etc)
Try to login to the ESXi using SSH and put the next commands:
Let us know the results.
Go to your proxy VM if you have one and release the VMDK files that correspond to the VM in question or Go to the VM directory and hit this command:- lsof | grep -i <VM-name>
Have a look if you have enough space in the datastore where the VM is stored. When you power on a VM it need free space to create the swap file. If your datastore is full it will not power on.
remove vm from inventory and re-register on other host then power on