Scenario:
System Center Operations Manager (SCOM) reports that the database integrity and copies are not healthy on some databases. Running the command Get-MailboxDatabaseCopyStatus shows everything to be healthy, however in the application eventlog, event ID 9877 is logged:
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Content Indexing function ‘CISearch::EcGetRowsetAndAccessor’ received an unusual and unexpected error code from MSSearch. Mailbox Database: [DB] Error Code: 0x80041606
Solution:
Navigate to services and find the Microsoft Exchange Search Indexer Service. Stop this service.
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Now Navigate to the folder where you database resides and delete the catalog folder, after that start the Search Indexer Service again and it will re-create the catalog. Depending on the size of the DB, it will crawl for a while and that error should be gone.
Hope it helps.
It worked for me, thanks !