This query should do the trick
USE EnterpriseVaultDirectory
SELECT A.ArchiveName, R.VaultEntryID, T.SID
FROM Archive A, Root R, Trustee T
WHERE A.RootIdentity = R.RootIdentity
AND R.OwningTrusteeIdentity = T.TrusteeIdentity
AND R.VaultEntryID NOT IN
(SELECT EME.DefaultVaultID FROM ExchangeMailboxEntry EME, Root R WHERE R.VaultEntryID = EME.DefaultVaultID)
https://www.linkedin.com/in/alex-allen-turl-07370146