TECISM

$errors = (Get-MsolContact –ObjectID <Object_ID>).Errors
$errors | foreach-object {“nService: " + $_.ErrorDetail.Name.split("/")[0]; "Error Message: "+ $_.ErrorDetail.ObjectErrors.ErrorRecord.ErrorDescription}

$errors = (Get-MsolGroup –ObjectID <Object_ID>).Errors
$errors | foreach-object {"nService: ” + $_.ErrorDetail.Name.split(“/”)[0]; “Error Message: “+ $_.ErrorDetail.ObjectErrors.ErrorRecord.ErrorDescription}

$errors = (Get-MsolUser -UserPrincipalName “<User_ID>”).Errors
$errors | foreach-object {“`nService: ” + $_.ErrorDetail.Name.split(“/”)[0]; “Error Message: ” + $_.ErrorDetail.ObjectErrors.ErrorRecord.ErrorDescription}

Get-MsolUser -HasErrorsOnly -All | ft DisplayName,UserPrincipalName,@{Name=”Error”;Expression={($_.errors[0].ErrorDetail.objecterrors.errorrecord.ErrorDescription)}} -AutoSize -wrap

https://support.microsoft.com/en-au/help/2741233/you-see-validation-errors-for-users-in-the-office-365-portal-or-in-the

Ensure you have a user mailbox backup prior to starting the following process as there is potential risk of data loss.  Options are to have a third party solution to perform a mailbox backup or export to PST (see new-mailboxexport cmdlet).

1. Capture relevant information from on-premise exchange and exchange online.
   • Grab the mailbox information (primary and archive) to help determine which mailbox is active and which one to disable (remove)
     • get-mailboxstatistics <user>
     • get-mailboxstatistics <user> -archive
     • get-exomailboxstatistics (exo ps v2)
   • Grab the x500 address (legacydn)
   • Grab GUID information
     • get-recipient <user> | fl *guid*
2. Determine which mailbox is active and which one to disable (remove) – 
   1. Removing the on-premise mailbox will require you to delete and recreate the remote mailbox – an object on-premise will need to represent the object on exchange for remote routing.
      1. Disable the on-premise mailbox – do not remove, or you will remove the AD user object:
         • disable-mailbox <user>
      2. If litigation hold is enabled, you will need to disable the hold, then disable the mailbox.
      3. Recreate the remote mailbox on-premise
         • Enable-RemoteMailbox -Identity <user> -RemoteRoutingAddress “<user>@<tenant>.mail.onmicrosoft.com”
      4. Associate the GUID and x500 for sync and mail routing:
         • Set-RemoteMailbox -exchangeguid <exchange guid> -archiveguid <archive guid>  -EmailAddresses X500: <x500>
   2. Removing the cloud mailbox
      1. Remove the user from Office 365 and resync with AD sync.
         • remove-msoluser <user>
         • remove-msoluser <user> -removefromrecyclebin -force
      2. Clearing the previous mailbox information
         • Set-User <user> -PermanentlyClearPreviousMailboxInfo

Accidentally deleted a on-premise mailbox?

1. Identify where the disconnected or soft deleted mailbox is. 
   • $dbs = Get-MailboxDatabase $dbs | foreach {Get-MailboxStatistics -Database $_.DistinguishedName} | where {$_.DisconnectReason -eq “Disabled”} | Format-Table DisplayName,Database,DisconnectDate
2. Reconnect the mailbox
   1. Connect-Mailbox -Identity “<identity>” -Database <database> -User “<user>” -Alias <alias>

Accidentally deleted the on-premise user, but need to restore the data to cloud mailbox?

1. Create a new temporary mailbox on-premise to restore the data to.
2. Identify where the disconnected or soft deleted mailbox is. 
   • $dbs = Get-MailboxDatabase $dbs | foreach {Get-MailboxStatistics -Database $_.DistinguishedName} | where {$_.DisconnectReason -eq “Disabled”} | Format-Table DisplayName,Database,DisconnectDate,*guid*
3. Restore the primary and archive data to the temporary mailbox
   • New-MailboxRestoreRequest -SourceStoreMailbox <mailbox guid> -SourceDatabase <database> -TargetMailbox <mailbox> -AllowLegacyDNMismatch
   • New-MailboxRestoreRequest -SourceStoreMailbox<mailbox guid> -SourceDatabase <database> -TargetMailbox <mailbox> -TargetIsArchive
4. Export the data to PST (requires rights) 
   • New–ManagementRoleAssignment –Role “Mailbox Import Export” –User Administrator
   • New-MailboxExportRequest -Mailbox <mailbox> -FilePath <path>
   • New-MailboxExportRequest -Mailbox <mailbox> -FilePath <path> -isarchive
     • Ensure the Exchange Trust Subsystem group has read/write permissions to path
5. Check status:
   • Get–MailboxExportRequest | where {$_.status –eq “Completed”}
6. Remove job:
   • Get-MailboxRestoreRequest -Status Completed | Remove-MailboxRestoreRequest
   • Get-MailboxRestoreRequest -Status Failed | Remove-MailboxRestoreRequest
7. Import to mailbox:
   • In Outlook with Exchange Online Mailbox, you can import directly – ensure you do not copy duplicates.