Failures on initial deduplication configuration: these types of failures and errors happen when setting up a new backup to a deduplicated vault or very shortly after.

• Run the same type of backup to a managed vault without Deduplication. If this backup also fails, the issue is not related to deduplication;
• Make sure that all backup Agents showing the failure have a proper deduplication license assigned;
• Make sure that the vault and database locations are fully accessible by the Storage Node service account.
  To check it, perform the next steps:

  
  

  1. Log on to Windows under Administrator account;
  2. Right click the folders which are the vault and database locations and select “Properties”;
  3. Open “Security” tab and highlight the ASN User (if there is no such user in the list, see below);
  4. Look at the permissions specified:

  
  

  If the user has no full control, do the following:

  1. On “Security” tab of the folder properties, click “Edit” button;
  2. Highlight the ASN User (if there is no such user in the list, see below);
  3. Tick the “Full control” check box and then click “OK” -> “OK” buttons.

  If there is no such user in the list at all, perform the following steps:

  1. On “Security” tab of the folder properties, click “Edit” button, then click the “Add…” button;
  2. Enter the name of ASN user or find the ASN User by clicking “Advanced” -> “Find now” buttons:
     
  3. Accept the changes and specify permissions for the ASN user by selecting “Full control” check box and then click “OK” button:
     

• Once all of the steps above are checked and the failure is still present, go to Collect information part.

Deduplication failures after a large amount of data has been deduplicated after a number of backups have been successfully created and indexed.

• Make sure that the ASN is not showing any crashes and that the vault is still fully available;
• Make sure that all Agents showing failures can access the vault;
• Make sure that indexing task is finishing correctly before the next backup task is started. If this is not the case, see this article;
• If the issue is not tied to performance, we are probably facing a problem with the existing deduplication data on this vault. Go to Collect information part below.