Find (disconnected) mailbox:
Get-MailboxServer | Get-MailboxStatistics | where { $_.DisconnectDate } | fl DisplayName, DisconnectDate
Recconnect mailbox:
Get-MailboxDatabase | Get-MailboxStatistics | Where-Object {$_.DisconnectDate –and $_.DisplayName –eq “Personal Archive – Tinnus Est”} | Connect-Mailbox –user T.Est –archive