This script moves folders with any date timestamp except for today, and moves it to a remote UNC path. Also checks free disk space and sends out notification email if under threshold - also checks for a file with fail*.* format that indicates another process failed to run properly.

#MoveFolders-EmailLowDiskFreeSpace.ps1

function CreateFailureFlagFile {
    $script:FailureFilePath = "$(Get-Location)\\_Failure-$(Get-Date -format yyyyMMdd).txt"
    ECHO 'Issue occured during processing of MoveFolders-EmailLowDiskFreeSpace.ps1 - Please refer to log file in same directory named TransferLog.txt' | Out-File -FilePath $FailureFilePath
}

function GetConfigs {
    try {
        $script:LogPath = Join-Path -Path $(Get-Location).Path -ChildPath "TransferLog.txt"

        MoveLogToOldLogIfLarge

        ECHO "`r`n" >> $LogPath
        ECHO "----------------------------------------------------------" >> $LogPath
        ECHO "Start: $(Get-Date -Format "yyyy-MM-dd HH:mm")" >> $LogPath
    
        $configJson = Get-Content '.\config.json' | Out-String | ConvertFrom-Json
    
        $script:DriveToCheckSpace = $configJson.TransferMonitor.DriveToCheckSpace
        $script:FreeSpaceThreshold = $configJson.TransferMonitor.FreeSpaceThreshold
        $script:FreeSpacePercThreshold = $configJson.TransferMonitor.FreeSpacePercThreshold
        $script:FailureFilePrefix = $configJson.TransferMonitor.FailureFilePrefix

        $script:SmtpServer = $configJson.Email.SmtpServer
        $script:EmailSender = $configJson.Email.EmailSender
        $script:EmailRecipients = $configJson.Email.EmailRecipients
        $script:EmailSubject = $configJson.Email.EmailSubject
        $script:EmailPriority = $configJson.Email.EmailPriority

        $script:FailureDetectedEmailBodyRaw = Get-Content -Raw $configJson.Email.FailureDetectedEmailBody
        $script:DiskSizeIssueEmailBodyRaw = Get-Content -Raw $configJson.Email.DiskSizeIssueEmailBody

        $script:SourceFolderPath = $configJson.MasterLogTransfer.SourceFolderPath
        $script:DestinationUNCPath = $configJson.MasterLogTransfer.DestinationUNCPath
    
        ECHO 'Successfully retrieved configuration parameters from config.json file.' >> $LogPath
    }
    catch {
        ECHO 'Failed to retrieve configuration parameters from config.json file.' >> $LogPath
        ECHO $_ >> $LogPath
        EXIT
    }
}

function NotifyIfAnyIssues {
    $Disks=Get-CimInstance -Class CIM_LogicalDisk | Select-Object @{Name="SizeGB";Expression={[math]::Round($_.size/1gb)}}, @{Name="FreeSpace";Expression={[math]::Round($_.freespace/1gb)}}, @{Name="FreePerc";Expression={[math]::Round(($_.freespace/1gb)*100 / ($_.size/1gb))}}, DeviceID, DriveType | Where-Object DriveType -EQ '3'
    $DiskToCheck=$Disks | Where-Object { $_.DeviceID -eq $DriveToCheckSpace}
    $FreeGB = $DiskToCheck.FreeSpace
    $FreePerc = $DiskToCheck.FreePerc
    $DiskSize = $DiskToCheck.SizeGB

    $emailParams = @{
	    SmtpServer = $SmtpServer
	    To = $EmailRecipients
	    From = $EmailSender
	    Priority = $EmailPriority
	    Subject = $EmailSubject
    }

    if ($(Get-ChildItem | Where {$_.Name.Contains("_Failure") -And $_.CreationTime -lt (Get-Date).AddMinutes(-5) }).Count -gt 0) { 
        ECHO '*** FAILURE *** Failure flag file detected in the folder where this process is running. Something has gone wrong in previous instances of this process.' >> $LogPath
        $FailureDetectedEmailBody = $ExecutionContext.InvokeCommand.ExpandString($FailureDetectedEmailBodyRaw) | Out-String
	    Send-MailMessage @emailParams -Body $FailureDetectedEmailBody -BodyAsHtml
    }

    if ($FreeGB -lt $FreeSpaceThreshold -Or $FreePerc -lt $FreeSpacePercThreshold) {
        ECHO '*** ISSUE *** Disk free space is lower than thresholds set in the config file.' >> $LogPath
        $DiskSizeIssueEmailBody = $ExecutionContext.InvokeCommand.ExpandString($DiskSizeIssueEmailBodyRaw) | Out-String
	    Send-MailMessage @emailParams -Body $DiskSizeIssueEmailBody -BodyAsHtml
    }
}

function MoveFoldersExceptTodayFolder {
    $OldFolder = dir $SourceFolderPath -Recurse -Depth 2 -Directory -Exclude .temp | Where { $_.Name.Length -eq 8 -AND $_.Name -ne $(Get-Date -Format yyyyMMdd) } 
        
    $OldFolder | ForEach-Object -Process { 
        $newFolderPath = Join-Path $DestinationUNCPath -ChildPath $_.FullName.Replace($SourceFolderPath,"")
        try { 
            $OldFolderCount = $(Get-ChildItem $_).Count

            MOVE -Force $_ $newFolderPath

            Get-Job | Wait-Job
            $NewFolderCount = $(Get-ChildItem $newFolderPath).Count

            if ($OldFolderCount -ne $NewFolderCount) {
                ECHO "*** FAILURE *** Number of files in the old folder [$_] do not match the destination folder [$newFolderPath]" >> $LogPath
                EXIT
            }
            ECHO "*** SUCCESS *** Successfully moved [$_] folder to destination folder [$newFolderPath]" >> $LogPath
            RM $FailureFilePath
        } catch {
            ECHO "*** FAILURE *** Failed to move [$_] folder to destination folder [$newFolderPath]" >> $LogPath
        }
    }
}

function MoveLogToOldLogIfLarge {
    if (-Not (Test-Path -Path $LogPath -PathType leaf)) { return };
    $LogSize = $(Get-Item $LogPath).Length
    if ($LogSize -gt 500000) {
        MOVE -Force $LogPath "$($LogPath.substring(0, $LogPath.length - 4)).old.txt"
    }
}

CreateFailureFlagFile

GetConfigs

NotifyIfAnyIssues

MoveFoldersExceptTodayFolder

config.json

{
	"MasterLogTransfer": {
		"SourceFolderPath": "C:\\Local-Folder",
		"DestinationUNCPath": "\\\\backup-server\folder",
		"LogFileName": "ProcessLog.txt"
	},
	"TransferMonitor": {
		"DriveToCheckSpace": "L:",
		"FreeSpaceThreshold": 5,
		"FreeSpacePercThreshold": 25,
		"FailureFilePrefix": "_fail"
	},
	"Email": {
		"SmtpServer": "IP or Hostname",
		"EmailSender": "[email protected]",
		"EmailRecipients": "Name Surname <[email protected]>",
		"EmailSubject": "Email Subject",
		"EmailPriority": "High",
		"FailureDetectedEmailBody": "Failure-Detected-EmailTemplate.html",
		"DiskSizeIssueEmailBody": "DiskSize-EmailTemplate.html"
	}
}

DiskSize-EmailTemplate.html

<!DOCTYPE html>
	<html>
		<head>
			<style> 
				body {
					font-family: Segoe UI Light, Tahoma, Arial, sans-serif;
				}
				table { 
					background-color: #EEE;
					border-collapse: collapse;
					width: 330px;
				} 
				td {
					width: 33%;
					border: 1px solid #DDD; 
					text-align: center;
				}
				th {
					background-color: #FFF;
				}
				code {
					font-family: Consolas;
					font-size: 110%
				}
				snap {
					font-family: courier-new;
				}

			</style>
		</head>
		<body>
			<title>Rhapsody Master Log - Drive Space</title>
			<h2>Free space needs to be checked for Rhapsody Master Logs</h2>
			<h4>Please check $DriveToCheckSpace on <code>NHRhapsodyProd.nh.org.au</code></h4>
			<table>
			<tr>
				<th></th>
				<th></th>
				<th>Threshold</th>
			</tr>
			<tr>
				<td>Drive</td>
				<td>$DriveToCheckSpace</td>
				<td></td>
			</tr>
			<tr>
				<td>Drive Size</td>
				<td>$DiskSize</td>
				<td></td>
			</tr>
			<tr>
				<td>Free Size (GB)</td>
				<td>$FreeGB</td>
				<td>$FreeSpaceThreshold</td>
			</tr>
			<tr>
				<td>Free Size (%)</td>
				<td>$FreePerc %</td>
				<td>$FreeSpacePercThreshold %</td>
			</tr>
			</table>
			<br/><br/>
			<h4>Please check the log in the following path on <code>NHRhapsodyProd.nh.org.au</code></h4>
			<snap>L:\Rhapsody Logs\MasterLog-Transfer\Processlog.txt</snap><br/><br/>
			<hr>
			<snap>Documentation available at: <a href="https://ictwiki.nh.org.au/index.php/Rhapsody_Master_Logs_move_to_the_Backup_Server">https://ictwiki.nh.org.au/index.php/Rhapsody_Master_Logs_move_to_the_Backup_Server</a></snap>
		</body>
	</html>

Failure-Detected-EmailTemplate.html

 <!DOCTYPE html>
	<html>
		<head>
			<style> 
				body {
					font-family: Segoe UI Light, Tahoma, Arial, sans-serif;
				}
				code {
					font-family: Consolas;
					font-size: 110%
				}
				snap {
					font-family: courier-new;
				}
			</style>
		</head>
		<body>
			<title>Rhapsody Master Log Move Failure!</title>
			<h2>Rhapsody Master Log Move Failure!</h2>
			<h4>Please check the log in the following path on <code>NHRhapsodyProd.nh.org.au</code></h4>
			<snap>L:\Rhapsody Logs\MasterLog-Transfer\Processlog.txt</snap><br/><br/>
			<hr>
			<snap>Documentation available at: <a href="https://ictwiki.nh.org.au/index.php/Rhapsody_Master_Logs_move_to_the_Backup_Server">https://ictwiki.nh.org.au/index.php/Rhapsody_Master_Logs_move_to_the_Backup_Server</a></snap>
		</body>
	</html>