When using third party backup solutions, they may create a lock on the VMX (configuration file) or VMDKs (data). In certain situations, the backup solution will retain the locks on the VM files and could cause the ESXi host locking from activating and the VMs will now power on.
VMware ESXi 7.x
VMware ESXi 8.x
Third party backup solutions are locking the VMX and/or VMDK files of VMs causing them to not power online and/or commit snapshots.
Pause and/or stop all backup tasks and attempt to power on the VMs affected via the vCenter, ESXi GUI or the CLI.
Check if there are any backup proxy VMs in the environment to see if it holds the vmdk files of the issue VMs.
Remove (do not delete) these vmdks from the backup proxy VM & then retry the task.
If there is still issue starting the VMs see the KBs in the additional information section for more information on resolving the issue.