Find-PartialEntryId.ps1

<#
.SYNOPSIS
    Finds a mailbox item using a partial EntryId and a message class.
.DESCRIPTION
    Corrupted items may have only a few properties and an EntryId that
    cannot be opened in MFCMapi. This often surfaces as a reminder that
    repeatedly shows up while the appointment for that reminder cannot
    be found.

    When other approaches fail, you can find the corrupted
    appointment by finding the reminder in MFCMapi and copying the last
    4 bytes (8 characters) of the PR_ENTRYID value. Use that value
    with this script, and this script will report the folder that
    contains the appointment in question.

    At that point, you can use MFCMapi to go to that folder, sort by
    Subject, and then delete the corrupted appointment. After the
    appointment is deleted, the reminder is gone.

    Note that it is usually necessary to disable the calendar version
    store to delete a corrupted appointment. Run:

    Set-Mailbox -CalendarVersionStoreDisabled $true

    This can take up to two hours to take effect. After that, the
    appointment can be deleted.
.EXAMPLE
    PS C:\> .\Find-PartialEntryId -Mailbox "Smith, Joe" -PartialEntryId "4C4DFA7A"
    Finds an appointment in the "Smith, Joe" mailbox with a matching EntryId.
.EXAMPLE
    PS C:\> .\Find-PartialEntryId -Mailbox "Smith, Joe" -PartialEntryId "4C4DFA7A" -MessageClass "IPM.Note"
    Finds an IPM.Note item in the "Smith, Joe" mailbox with a matching EntryId.
#>
[CmdletBinding()]
param (
    [Parameter(Mandatory = $true)]
    [string]
    $Mailbox,

    [Parameter(Mandatory = $true)]
    [string]
    $PartialEntryId,

    [Parameter()]
    [string]
    $MessageClass = "IPM.Appointment"
)

. $exscripts\ManagedStoreDiagnosticFunctions.ps1

$mb = Get-Mailbox $Mailbox

$mbTableResult = Get-StoreQuery -Database "$($mb.Database.ToString())" -Query "SELECT MailboxNumber FROM Mailbox WHERE MailboxGuid = '$($mb.ExchangeGuid.ToString())'"

Write-Host "Found mailbox $($mb.DisplayName) with mailbox number $($mbTableResult.MailboxNumber)."

$mailboxNumber = $mbTableResult.MailboxNumber

$messageTableResult = @(Get-StoreQuery -Database "$($mb.Database.ToString())" -Query "SELECT FolderId,MessageId FROM Message WHERE MailboxNumber = $mailboxNumber AND MessageClass = `"$MessageClass`"" -Unlimited | Where-Object {
        $_.MessageId.ToString() -like "*$($PartialEntryId)*"
    })

Write-Host "Found $($messageTableResult.Length) message table results with matching EntryId."

$folderTableResults = Get-StoreQuery -Database "$($mb.Database.ToString())" -Query "SELECT FolderId,ParentFolderId,DisplayName FROM Folder WHERE MailboxNumber = $mailboxNumber" -Unlimited

$folderPath = ""
$currentId = $messageTableResult.FolderId
$matchingFolder = $null

do {
    $matchingFolder = @($folderTableResults | Where-Object { $_.FolderId -eq $currentId })
    if ($matchingFolder.Length -gt 0) {
        $folderPath = $matchingFolder.DisplayName + "\" + $folderPath
        $currentId = $matchingFolder.ParentFolderId
    }
} while ($matchingFolder.Length)

Write-Host "Item was found in folder: $folderPath"