Providing status updates for macro that goes into not responding state until completion

Question

I have a VBA Macro to search through email archives.

When searching through tens of thousands of emails, (or even just a couple hundred on my test machine) it displays the status for a few seconds, then enters a Not Responding state while running through the rest of the emails.

This has led impatient users to close out of the task prematurely, and I would like to rectify this by providing status updates.

I have coded the following solution, and believe that the problem lies in the way the GarbageCollector functions in VBA during the Loop.

Public Sub searchAndMove()

    UserForm1.Show

    ' Send a message to the user indicating
    ' the program has completed successfully, 
    ' and displaying the number of messages sent during the run.

End Sub

Private Sub UserForm_Activate()

Me.Width = 240
Me.Height = 60

Me.Label1.Width = 230
Me.Label1.Height = 50

Dim oSelectTarget As Outlook.Folder
Dim oMoveTarget As Outlook.Folder
Dim oSearchCriteria As String

' Select the target folder to search and then the folder to
' which the files should be moved
Set oSelectTarget = Application.Session.PickFolder
Set oMoveTarget = Application.Session.PickFolder

oSearchCriteria = InputBox("Input search string: ")

Dim selectedItems As Outlook.Items
Set selectedItems = oSelectTarget.Items
Dim selectedEmail As Outlook.MailItem

Dim StatusBarMsg As String
StatusBarMsg = ""

Dim initialCount As Long
initialCount = selectedItems.count


Dim movedCounter As Long
movedCounter = 0
Dim x As Long
Dim exists As Long

' Function Loop, stepping backwards
' to prevent errors derived from modifying the collection
For x = selectedItems.count To 1 Step -1
    Set selectedEmail = selectedItems.Item(x)
    ' Test to determine if the subject contains the search string

    exists = InStr(selectedEmail.Subject, oSearchCriteria)
    If Len(selectedEmail.Subject) > 999 Then
        selectedEmail.Move oMoveTarget
    Else:
        If exists <> 0 Then
            selectedEmail.Move oMoveTarget
            movedCounter = (movedCounter + 1)
        Else: End If
    End If
    Set selectedEmail = Nothing
    StatusBarMsg = "Processing " & x & " out of " & initialCount & " messages."

    UserForm1.Label1.Caption = StatusBarMsg
    UserForm1.Repaint
Next x

Dim Msg As String
Dim Response
Msg = "SearchAndMove has detected and moved " & movedCounter & _
  " messages since last run."
Response = MsgBox(Msg, vbOKOnly)


' Close the References to prevent a reference leak
Set oSelectTarget = Nothing
Set oMoveTarget = Nothing
Set selectedItems = Nothing
Set selectedEmail = Nothing

Unload Me

End Sub

Answer 1

Change the line

UserForm1.Repaint

to

DoEvents

Yes this will increase the execution time but in case there are thousands of emails then you don't have much of an option.

TIP: Also you might want to change

StatusBarMsg = "Processing " & x & " out of " & initialCount & " messages."

to

StatusBarMsg = "Please do not interrupt. Processing " & x & " out of " & initialCount & " messages."

Also it is advisable to inform your user at the beginning of the process that it might take time and hence they can run the process when they are sure they do not want to work on that pc?

Something like this

Sub Sample()
    Dim strWarning As String
    Dim Ret

    strWarning = "This process may take sometime. It is advisable to run this " & _
    "when you don't intend to use the pc for sometime. Would you like to Continue?"

    Ret = MsgBox(strWarning, vbYesNo, "Information")

    If Ret <> vbYes Then Exit Sub

    For x = SelectedItems.Count To 1 Step -1

    '~~> Rest of the code
End Sub

HTH

Sid