I see almost all the vm are showing as invalid. This could be because of the storage unavailability. Do you see all the datastore visible in the vcenter?
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What is the full error you are seeing after logs 'cannot open disk' path..... like snapshots or parent disk, something like this !
Please see the issues in this KB if this is one of them : Cannot power on a VM because the virtual disk cannot be opened (1004232) | VMware KB