Create a folder on the computer that will perform the backup removal task. This folder will contain the backup removal script and the log file.

Start the script editor, and then copy and paste the following code example into the editing window:

'       Title: BackupCleanUp
' Description: Deletes SharePoint 2007 backups older than a specified 
'              number of days and removes them from the backup history. 

Dim nNumberOfDays
Dim strTOCFile
Dim dtDeleteDate

Set objXML = CreateObject("Microsoft.XMLDOM")
Set objFS  = CreateObject("Scripting.FileSystemObject")
Set objLog = objFS.OpenTextFile("BackupCleanUp.log",8,true)

' Validate Command Line Arguments and Initialize Data
If WScript.Arguments.Count = 2 Then
    If IsNumeric(WScript.Arguments(0)) Then   
        nNumberOfDays = CInt(WScript.Arguments(0))
        dtDeleteDate = DateAdd("d",nNumberOfDays*-1,Now)
    Else
        WScript.Echo "<NumberOfDays> must be an integer value."
    End If
        strTOCFile = WScript.Arguments(1)
Else
    WScript.Echo "Usage: BackupCleanUp <NumberOfDays> <PathToTOC>"
    WScript.Quit
End If

objLog.WriteLine(Now() &vbTab& "Start: Clean up backups older than " &nNumberOfDays& " days from " &strTOCFile& ".")

' Load SharePoint Backup and Restore TOC File
objXML.Async = false
objXML.Load(strTOCFile)

If objXML.ParseError.ErrorCode <> 0 Then
    objLog.WriteLine(Now() &vbTab& "Error: Could not load the SharePoint Backup / Restore History." &vbCrLf&_
                     Now() &vbTab& "Reason: " &objXML.ParseError.Reason& ".") 
    WScript.Quit
End If

' Delete Backup Nodes Older Than Deletion Date
For Each objNode in objXML.DocumentElement.ChildNodes
    If CDate(objNode.SelectSingleNode("SPFinishTime").Text) < dtDeleteDate Then
        If objNode.SelectSingleNode("SPIsBackup").Text = "True" Then
            objFS.DeleteFolder(objNode.SelectSingleNode("SPBackupDirectory").Text)
            objLog.WriteLine(Now() &vbTab& "Deleted: " &objNode.SelectSingleNode("SPBackupDirectory").Text& ".")
            objXML.DocumentElement.RemoveChild(objNode)
        End If     
    End If
Next

' Save XML File With Old Nodes Removed
objXML.Save(strTOCFile)
objLog.WriteLine(Now() &vbTab& "Finish: Completed backup clean up.")

You can edit the script as necessary to meet the requirements of the network, equipment, retention policies, or service agreements.

Save the file as BackUpCleanUp.vbs in the folder that you created earlier.

At a command prompt, change to the directory that contains the BackUpCleanUp.vbs file.

Type the following command, and then press ENTER:

Cscript.exe BackUpCleanUp.vbs <Number of days> <\\server name\folder name>

where <Number of days> is the maximum age of the backup files you want to keep (backup files older than this will be deleted by the BackUpCleanUp script) and <\\server name\folder name> is the path of the spbrtoc.xml backup manifest file.

To troubleshoot the backup file removal process or to review progress, open the BackUpCleanUp.log file located in the same folder.

Start the Scheduled Tasks Wizard, double-click Add Scheduled Task, and then click Next.

Click Browse, navigate to %ROOT%\WINNT\System32\cscript.exe, and then click Open.

Type a name for the task, for example, BackUpCleanUp.

To automatically perform this backup periodically, select an interval such as Weekly or Monthly, and then click Next. To perform this backup one time, or to delay a single backup, select One time only.

Choose a time and start date for the task, and then click Next.

Type a user name and password in the appropriate boxes, confirm the password, and then click Next. This task will run as if it were started by that user.

Select Open advanced properties for this task when I click Finish, and then click Finish.

In the Advanced Properties dialog box, on the Task tab, in the Run text box, type the following command:

Cscript.exe BackUpCleanUp.vbs <Number of days> <\\server name\folder name>

where <Number of days> is the maximum age of the backup files that you want to keep (backup files older than this will be deleted by the BackUpCleanUp script) and <\\server name\folder name> is the path of the spbrtoc.xml backup manifest file.

In the Start In text box, type the path of the folder where the BackUpCleanUp.vbs file is located.

Select Enabled (scheduled task runs at specified time), and then clear the Run only if logged in check box.

Click OK.