This error occurs from time to time, but can be rectified quickly. So if you see this error in the event log, you can quickly repair the index using the commands below
Event ID: 123
Source: ExchangeStoreDB
Info: A corrupted search catalog has been used for the copy of the Microsoft Exchange information store database on this server.
In this case, it is not necessary to transfer the complete database copy again, but the index is sufficient, so first briefly check the status of the database:
Get-MailboxDatabaseCopyStatus TEST-MBX
On the screenshot you can see that the ContentIndex is damaged, but intact on the other server. Only the index can be transferred with the following command:
Update-MailboxDatabaseCopy Test-MBX\KAPUTTERSERVER -CatalogOnly
After seeding, everything should be fine again.
