When deploying a GPO with GPOADmin you may receive the same or similar error as shown below.
Quest.Avalanche.Exceptions.AvalancheException: Error importing settings to object. ---> System.Runtime.InteropServices.COMException: The directory is not empty. (Exception from HRESULT: 0x80070091)
at GPOADmin.Interops.GpmGmt.GPMResultClass.OverallStatus()
at Quest.Avalanche.ClassLibrary.LiveEnvironment.PolicyBase.ImportGpmBackup(Backup backup, String migrationTable, Boolean migrationTableOnly, Boolean validateImport)
at Quest.Avalanche.ClassLibrary.LiveEnvironment.PolicyBase.DoInternalImport(Backup backup, String migrationTable, Boolean migrationTableOnly, Boolean migrateSecurityFiltering, PolicyData data, PolicyData backupData)
at Quest.Avalanche.ClassLibrary.LiveEnvironment.PolicyBase.ImportInternal(Backup backup, String migrationTable, Boolean migrationTableOnly, Boolean migrateSecurityFiltering)
at Quest.Avalanche.ClassLibrary.LiveEnvironment.VersionControllable.Import(Backup backup, String migrationTable, Boolean migrationTableOnly, Boolean migrateSecurityFiltering)
--- End of inner exception stack trace ---
Also when testing the import using the native Group Policy Management Console (GPMC), an error occurs.