"InvalidOperationException" and Store Worker process crashes during mailbox move (KB5004615)

Symptoms

Consider the following scenario in Microsoft Exchange Server 2019:

• In Exchange Management Shell, you run the following command:
  
  Set-TransportConfig -MaxReceiveSize unlimited
  
  Note: You might have to restart the services or wait a short while for the configuration to take effect.

• You create a mailbox or use an existing mailbox.

• You move the new mailbox from one database to another database (for example, by running new-moverequest user1 -targetdatabase DB2 -Priority High).

In this scenario, the Store Worker process crashes and generates an InvalidOperationException error. This problem causes the database to dismount and the user to be disconnected. Additionally, Event ID 4999 is logged in the event log.

Resolution

To fix this issue, install the following cumulative update:

Cumulative Update 10 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019

Symptoms

In Microsoft Exchange Server 2016, the Store Worker process for active databases crashes and generates an unhandled System.InvalidOperationException error on some database availability group (DAG) members when they load folder cache.

Cause

This error occurs because certain logic in the process tries to delete information for an already missing index.

Resolution

To fix this issue, install the following cumulative update:

Cumulative Update 21 for Exchange Server 2016 or a later cumulative update for Exchange Server 2016.