My configuration is Exchange 2010 SP1, Windows Server 2008 R2 SP1. All MS Exchange roles are assigned to one MS Exchange Server with Antivirus and Antispam SW together. Except this problem everything looks fine. In Application Log on my MS Exchange Server, I have 4 reoccurring logs /always all together/: Event ID: 1025, Source: MSExchangeIS Mailbox Store An error occurred on database "Mailbox Database 1073144232". Function name or description of problem: Cannot generate Read Notification when Sender Data is missing!!!! Error: 0x8004010f Event ID: 1025, Source: MSExchangeIS Mailbox Store An error occurred on database "Mailbox Database 1073144232". Function name or description of problem: EcSetRNProps: Error: 0x8004010f Event ID: 1025, Source: MSExchangeIS Mailbox Store An error occurred on database "Mailbox Database 1073144232". Event ID: 1025, Source: MSExchangeIS Mailbox Store An error occurred on database "Mailbox Database 1073144232". Function name or description of problem: EcGenerateNRN: I have found problems, solutions, symptoms with the same Event ID, but only for MS Exchange 2003, or older. I tried to apply these solutions in MS Exchange 2010, but with no success. I defragmented database with ESEUTIL, I ran ISINTEG in Exchange 2010 SP1 is it New-MailboxRepairRequest cmdlet. I tried to check permissions with Best Practices Analyzer but no security, or security related errors found. No success.