Add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010

$ExSystems=(Get-ExchangeServer).name

$ExDbs=@()
foreach ($ExSystem in $ExSystems)
    {
    $ExDbs+=Get-MailboxDatabaseCopyStatus -server $ExSystem 
    }

$failedCIState = $ExDbs | where-object contentindexstate -like "failed"

foreach ($failed in $failedCIState)
    {
    Update-MailboxDatabaseCopy "$($failed.name)" -CatalogOnly
    }