When you disable a mailbox, Exchange Server continues to keep the mailbox in the mailbox database and puts the mailbox in disabled state. Exchange corresponding attributes Active Directory is also removed from the user account, but the user account is preserved.
The mailbox will remain in the mailbox database until the deleted mailbox retention period expires, which is 30 days by default, before it is permanently deleted from the mailbox database (or without being cleaned) continues to be stored first.
Reactivating Deleted Mail Account in Exchange Server
Until a disabled mailbox is permanently deleted from the Exchange mailbox database, you can reconnect it to the Active Directory user account by using the EAC or the Exchange Management Shell.
A disabled MBX can access the EAC Connect to Mailbox We can reactivate it with the button.
But sometimes due to the delay between Exchange Server and Active Directory, disabled MBX Connect does not appear in the mailbox section.
Microsoft describes this issue as follows: “It is possible that the storage state of a mailbox is not synchronized with the state of the corresponding Active Directory user account. This can be due to Active Directory replication latency. For example, if a user account that has a mailbox enabled is disabled in Active Directory, but is not marked as disabled in the Exchange mailbox store. In this case, running the Update-StoreMailboxState command synchronizes the mailbox store state with the state of the Active Directory user account and marks the mailbox as disabled in the mailbox store. You can use this command to troubleshoot issues that may occur when the storage state of a mailbox is unexpected or if you suspect that the store state is different from the state of the corresponding Active Directory account.”
In a scenario where the mailbox is moved to another database and then immediately disabled, there is a 24-hour delay to allow for replication.
Updating Mail Accounts That Are Not Showing in Connect a Mailbox
To solve this problem, run EMS.
To learn the GUID of the disabled MBX, you need to run the following command set.
Get-MailboxDatabase | Get-MailboxStatistics | Where { $_.DisplayName -eq "HCtestmailbox" } | fl DisplayName,Database,DisconnectReason,DisconnectDate,MailboxGuid
The first command we run is to create a mailbox database and GUIDwill display the results, then the GUID found in the output is copied and run with the following command set.
Update-StoreMailboxState -Database “Mailbox Database Name” -Identity “Mailbox GUID”
You can then reactivate the mail account that you disabled by filtering the server where it is located from the Connect to mailbox section.