Exchange 2010 Mailbox Database in DAG Error: content index catalog files in the following state: 'Failed'.

Issue:
when you tru to move the active copy from a mailbox server to another server you get error:

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Microsoft Exchange Error
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Cannot activate database copy 'Activate Database Copy...'.

Activate Database Copy...
Failed
Error:
An Active Manager operation failed. Error: The database action failed. Error: An error occurred while trying to validate the specified database copy for possible activation. Error: Database copy 'DB Name' on server 'servername' has content index catalog files in the following state: 'Failed'.

To Resolve it:
1. Restart the MSExchange Search service on the node which has the active database.
2. Run update-mailboxdatabasecopy -catalogonly for the passive database