VM cloning operation failed with error: "The operation is not allowed in the current state of the datastore"

Products

• VMware vCenter Server

Issue/Introduction

• Unable to clone any VM in the cluster. Cloning operation fails with the following error - "The operation is not allowed in the current state of the datastore". 
• Cluster has Storage DRS enabled.
• VM cloning task fails with the below error:

• Below error can be seen in /var/log/vmware/vpxd/vpxd.log in vCenter Server Appliance:

yyyy-mm-ddTss:ss:ss.070+02:00 error vpxd[####] [Originator@### sub=Default opID=######] [VpxLRO] -- ERROR task-#######-- vm-<vm_id> -- vim.VirtualMachine.clone: :vim.fault.InvalidDatastoreState

yyyy-mm-ddTss:ss:ss.531+02:00 error vpxd[#####] [Originator@### sub=VmProv opID=#####] Local-VC Full Clone failed at vpx.vmprov.SelectDestination for poweredOn VM 'VM_name' (vm-id, ds:///vmfs/volumes/UUID/VM/VM_name.vmx) to new name <VM name> on host-ID in pool resgroup-ID with ds ds:///vmfs/volumes/UUID/ to (DstLocation null) with fault vim.fault.InvalidDatastoreState

Environment

VMware vCenter Server 
VMware vSphere ESX

Cause

This issue occurs when the datastore is in maintenance mode or is not accessible/readable.

Resolution

Exit the datastore out of the maintenance mode or remove datastore if it is no longer required.

Additional Information

Refer to the following document to check if the datastore is readable: Storage vMotion compatibility Error: "The operation is not allowed in the current state of datastore"