Script to dump email from an exchange Mailbox using EWS. This is script from 2014

DumpMailboxEmail.ps1

Import-Module  -Name 'C:\PowerShell\Modules\EWSModule\EWSModule.psm1'
###Requires -Modules EWSModule
function Get-cDumpMailboxEmail
{
    [CmdletBinding()]
    Param(
        [Parameter(Mandatory = $true,
        Position = 0)]
        $OutputPathRoot,
        [pscredential]
        $Credential = (Get-Credential)
    )

    Begin{
        $ErrorActionPreference = 'Stop'

        if(!(Test-Path $OutputPathRoot))
        {
            Write-Error  -Message 'Unable to Find OutputRoot - Check your path'
        }

        $lastDownload = $false
        $lastDownloadID = $null
        $foundEmail = $null
        $lastCheckedFile = "C:\PowerShell\Logs\DumpLastChecked.txt"
        $mailBox = '[email protected]'
        $exchCasFQDN = 'mail.example.com'

        if(Test-Path -Path $lastCheckedFile)
        {
            $lastDownloadID = (Get-Content  -Path $lastCheckedFile )[0]
            $lastDownloadDate = Get-Date  -Date (Get-Content  -Path $lastCheckedFile)[1]
      
            $aqsString = "received:>=$(Get-Date -Date $lastDownloadDate -Format g)"
            $lastDownload = $true

            Write-Verbose  -Message "Last Checked Email: $lastDownloadID"
            Write-Verbose  -Message "Last Checked Date: $lastDownloadDate"
            Write-Verbose  -Message "AQS Query: $aqsString"
        }
        
        
            
    }
    
    Process{

        $EWSService = Connect-EWS -Credential $Credential -CASFQDN $exchCasFQDN -ExchangeVersion Exchange2010_SP2  
        if($lastDownload)
        {
            $foundEmails = Search-EWS -EWSService $EWSService -MailBoxAddress $mailBox -AQS $aqsString -ViewLimit 1000
        }
        else
        {
            $foundEmails = Search-EWS -EWSService $EWSService -MailBoxAddress $mailBox -ViewLimit 1000
        }

        #read oldest first
        $firstRun = $true
        for($i = $foundEmails.Length-1;$i -ge 0;$i--)
        {
            #Weird Bug with EWS or PowerShell array??
            if($i -eq 0 -and $firstRun)
            {
                $foundEmail = $foundEmails
            }
            else
            {
                $foundEmail = $foundEmails[$i]
                $firstRun = $false
            }
            #if($foundEmail.Id -eq $lastDownloadID)
            #{
            #    Write-Verbose  -Message 'Hit the marker'
            #    break
            #}
            # RegEX Match 6 Digit EmployeeID in Email Subject
            if([Regex]::Matches($foundEmail.Subject, '\b\d{6}\b').Count -eq 1)
            {
                $emplId = [Regex]::Match($foundEmail.Subject, '\b\d{6}\b').Value

                #check to see if $employeeID from email subject match with AD record
                #if(Get-ADUser -Filter {EmployeeNumber -eq $emplId}){

                    Write-Verbose  -Message "Email Found - $($foundEmail.Subject)"

                    #Load Email Full Content.
                    $foundEmail.Load()

                    $recievedDateFormat = Get-Date  -Date $foundEmail.DateTimeReceived -Format MM-dd-yyyy_HHmmss
                
                    #Create Folder Based on ID from Email subject

                    $folderPath = New-Folder -path $OutputPathRoot -folderName $emplId

                    #Massage FileName based on Subject and remove any special character

                    if($foundEmail.Subject -eq $null)
                    {
                        $emailOutput = "$folderPath\No Subject ($recievedDateFormat).eml"
                    }
                    else 
                    {
                        #Replace \ character from Subject then set filename
                        if($foundEmail.Subject.Length -gt 15){
                            $emailOutputPartitalName = $(($foundEmail.Subject -replace '[^a-zA-Z0-9_\(\)\- ]').Substring(0,15))
                        }else{
                            $emailOutputPartitalName = $($foundEmail.Subject -replace '[^a-zA-Z0-9_\(\)\- ]')
                        }
                        $emailOutput = "$folderPath\($recievedDateFormat) $emailOutputPartitalName.eml"
                    }


                    #Save Email Content Byte[] into File

                    if(!(Test-Path $emailOutput))
                    {
                        Write-Verbose  -Message "Writing Email to Disk: $emailOutput"
                        #$foundEmail |
                        #Get-EWSEmailContentAsByte | Set-Content -Path $emailOutput -Encoding Byte
                        $propSet = New-Object Microsoft.Exchange.WebServices.Data.PropertySet([Microsoft.Exchange.WebServices.Data.ItemSchema]::MimeContent)
                        $foundEmail.load($propSet)
                        #$foundEmail.MimeContent.Content | Set-Content -Path $emailOutput -Encoding Byte
                        #$foundEmail | Get-EWSEmailContentAsByte 
                        #$emlByte = $foundEmail | Get-EWSEmailContentAsByte
                        $fiFile = new-object System.IO.FileStream($emailOutput, [System.IO.FileMode]::Create)
                        $fiFile.Write($foundEmail.MimeContent.Content, 0, $foundEmail.MimeContent.Content.Length)
                        $fiFile.Close()
                        $fiFile.Dispose()
                    }
                    #Saving Attachment(s)

                    $attachments = Get-EWSAttachments -EmailMessages $foundEmail
                    foreach($attachment in $attachments)
                    {
                        if(($attachment.Content) -ne $null){
                            Write-Verbose  -Message 'Attachment Found'
                            $fileNameSplit = $attachment.filename.Split('.')
                            $filenameExt = $fileNameSplit[$fileNameSplit.length-1]
                            $filenameWOext = $attachment.filename -Replace ".$filenameExt"
                            $attachmentOutput = "$folderPath\($recievedDateFormat) $filenameWOext.$filenameExt"
                            if(!(Test-Path $attachmentOutput))
                            {
                                Write-Verbose  -Message "Write Attachment to Disk: $attachmentOutput"

                                $fiFile = new-object System.IO.FileStream($attachmentOutput, [System.IO.FileMode]::Create)
                                $fiFile.Write($attachment.Content, 0, $attachment.Content.Length)
                                $fiFile.Close()
                            }
                         }
                    }

                    #Write-Output  -InputObject $foundEmail
                #}
            }

            #Last Download/Check Marker
            $lastCheckedEmail = "$($foundEmail.Id)`r`n$($foundEmail.DateTimeReceived)"
                
            $lastCheckedEmail | Set-Content -Path $lastCheckedFile -Encoding Ascii -Force

            Write-Verbose  -Message "***Last Checked Email: $lastCheckedEmail"
        }
    }
}
function New-Folder
{
    param
    (
        [String]
        $path,

        [String]
        $folderName
    )

           
    if(!(Test-Path  -Path "$path\$folderName"))
    {
        $newFolder = "$path\$folderName"
        Write-Verbose  -Message "Creating Folder $newFolder"
        return (New-Item -Path $newFolder -ItemType Directory).ToString()
    }
    else
    {
        return "$path\$folderName"
    }
}


function Test-cDumpMailboxEmail
{
    Get-cDumpMailboxEmail -OutputPathRoot 'C:\PowerShell\TestFolder' -Credential (Import-Clixml  -Path 'emailcred.xml') -Verbose
}


try{
Get-cDumpMailboxEmail -OutputPathRoot '\\example\dumpEmails' -Credential (Import-Clixml  -Path 'C:\PowerShell\Cred\cred.xml' ) -Verbose
}catch{

    Send-MailMessage -To '[email protected]' -From '[email protected]' -Subject 'Error with DumpMailbox' -Body "$error[0]" -SmtpServer smtp.example.local

}