Hello @SHAREPOINTER ,
According to my understanding of your problem, when you performing a full backup, you find backup errors involving the Search Service database.
1.Identify the Search Service Account.
2.Navigate to the intranet folder to which you intend to write full farm backups
3Grant the Search Service Account the following permissions to this folder:
For more information, please see this post "SharePoint 2013: FatalError: Object Search Service failed in event OnBackup".
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