It's in the registry and I it's called "pendingfilerenameoperation" or just "pendingfilerename". We may look in a couple of places in the registry where this key can exist, so search the entire registry for it to find all instances.
I've found the following entry. Based upon its value, I am wondering if we look at this entry, and then trace the path its value is set to, and look in that area of the registry (or if we go directly to CurrentControlSet\Control\Session Manager\PendingFileRenameOperations and look there).
Key: HKLM\SYSTEM\CurrentControlSet\Control\BackupRestore\KeysNotToRestore\Pending Rename Operations
The machine I browsed did not have anything under CurrentControlSet\Control\Session Manager\PendingFileRenameOperations, but I assume if there were entries in this area, that would mean the system needs to be rebooted.