No errors are logged.
When a new index snapshot is created, it creates multiple files, i.e. .dat(meta and snap), files under the indices folder, and a corresponding States_Guid folder. The GUID denotes the snapshot name and this folder contains a stat.dat file for each of the index volumes. When the index snapshot expiry runs, it deletes the .dat (meta and snap) file and the content of the 'Indices' folder. But the expiry does not delete the "States_snapshotname" created for each of these snapshots.
After a new snapshot is created :
After snapshot expiry is run :
This was the default behavior till Enterprise Vault version 15.1.
This issue has been addressed in the following release: