VBA events stop working for one user when another user opens the shared workbook

Based on your detailed description, this appears to be a known limitation in Excel's shared workbook functionality when combined with VBA events. Is a classic symptom of Excel's legacy shared workbook architecture, and your diagnostic work is excellent.

You've correctly identified the core issue: when a workbook enters legacy shared mode (Review > Share Workbook), Excel forcibly disables all VBA events at the engine level. This is by design, not a bug. Microsoft implemented this to prevent data corruption that could occur if multiple users triggered simultaneous event-driven code.

Key points from your observations that confirm this:

• Application.EnableEvents returns True but events don't fire (Excel overrides this setting in shared mode)
• Manual macros work perfectly (they don't rely on automatic triggers)
• The issue started precisely when a second user opened the file (the moment it became shared)

When your employee opens the file, Excel transitions it into shared mode. From that moment forward:

• Your session: Events are disabled at the C++ level, regardless of VBA settings
• Employee's session: Same limitation applies to them
• The file appears to work for them because they likely haven't tested events while you're both in the file, or they're using different functionality.

While we cannot override Excel's fundamental architecture, here are a approach that provide partial functionality:

Workaround with a switch…

This is the most practical because it:

• Requires zero changes to existing CRM logic
• Automatically detects when to use events vs buttons
• Takes 5 minutes to implement
• Works immediately for both users

' =============================================
' SMART CRM SWITCH - PASTE IN THISWORKBOOK MODULE
' =============================================

Private Sub Workbook_Open()
    ' CRITICAL: Check shared status immediately
    If ThisWorkbook.MultiUserEditing Then
        ' We're in shared mode - events disabled, switch to button mode
        Call EnableButtonMode
    Else
        ' Exclusive mode - events work perfectly
        Call EnableEventMode
    End If
End Sub

Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
    ' Prevent accidental saving in wrong mode
    Static lastWarning As Date
    
    If ThisWorkbook.MultiUserEditing Then
        ' In shared mode - that's fine, just warn about events
        If DateDiff("s", lastWarning, Now) > 300 Then ' Every 5 minutes
            MsgBox "Reminder: You're in shared mode." & vbCrLf & _
                   "• Use the CRM toolbar buttons for updates" & vbCrLf & _
                   "• Automatic events are disabled", _
                   vbInformation, "CRM System"
            lastWarning = Now
        End If
    End If
End Sub

' =============================================
' MODE MANAGEMENT
' =============================================

Private Sub EnableButtonMode()
    ' Show toolbar for manual operations
    Call CreateCrmToolbar(True)
    
    ' Notify user ONCE per session
    Static notified As Boolean
    If Not notified Then
        MsgBox "CRM: MULTI-USER MODE ACTIVE" & vbCrLf & _
               "• Multiple people can edit simultaneously" & vbCrLf & _
               "• Please use the CRM toolbar (top of screen)" & vbCrLf & _
               "• Automatic updates are temporarily disabled", _
               vbInformation, "CRM System"
        notified = True
    End If
End Sub

Private Sub EnableEventMode()
    ' Hide toolbar, use automatic events
    Call CreateCrmToolbar(False)
    
    ' Ensure events are enabled
    Application.EnableEvents = True
    
    ' Brief confirmation (optional)
    ' Debug.Print "Exclusive mode - events active at " & Now
End Sub

' =============================================
' CRM TOOLBAR (YOUR BUTTON INTERFACE)
' =============================================

Private Sub CreateCrmToolbar(ShowIt As Boolean)
    On Error Resume Next
    
    ' Remove existing toolbar if any
    Application.CommandBars("CRM Tools").Delete
    On Error GoTo 0
    
    If Not ShowIt Then Exit Sub
    
    ' Create new toolbar
    Dim cb As CommandBar
    Set cb = Application.CommandBars.Add("CRM Tools", msoBarTop, Temporary:=True)
    
    ' Add your CRM buttons (customize these!)
    With cb.Controls.Add(msoControlButton)
        .Caption = "Add Customer"
        .FaceId = 211
        .OnAction = "CRM_AddCustomer"
        .TooltipText = "Add new customer record"
        .Style = msoButtonIconAndCaption
    End With
    
    With cb.Controls.Add(msoControlButton)
        .Caption = "Edit Customer"
        .FaceId = 213
        .OnAction = "CRM_EditCustomer"
        .TooltipText = "Edit selected customer"
        .Style = msoButtonIconAndCaption
    End With
    
    With cb.Controls.Add(msoControlButton)
        .Caption = "View All"
        .FaceId = 215
        .OnAction = "CRM_ViewAll"
        .TooltipText = "View all customers"
        .Style = msoButtonIconAndCaption
    End With
    
    With cb.Controls.Add(msoControlButton)
        .Caption = "Reports"
        .FaceId = 217
        .OnAction = "CRM_Reports"
        .TooltipText = "Generate reports"
        .Style = msoButtonIconAndCaption
    End With
    
    cb.Visible = True
End Sub

' =============================================
' YOUR EXISTING CRM CODE (ADAPTED FOR BUTTONS)
' =============================================

' These subs should contain your existing Worksheet_Change logic
' Just moved to button-triggered operations

Public Sub CRM_AddCustomer()
    ' PASTE YOUR EXISTING "ADD CUSTOMER" CODE HERE
    ' This is whatever you normally do when adding a customer
    
    ' Example:
    Dim newRow As Long
    newRow = Sheets("Customers").Range("A" & Rows.Count).End(xlUp).Row + 1
    
    ' Simple input form
    Dim custName As String
    custName = InputBox("Enter customer name:", "Add Customer")
    
    If custName <> "" Then
        Sheets("Customers").Cells(newRow, 1) = custName
        Sheets("Customers").Cells(newRow, 2) = Date
        Sheets("Customers").Cells(newRow, 3) = Environ("Username")
        
        MsgBox "Customer added successfully!", vbInformation
    End If
End Sub

Public Sub CRM_EditCustomer()
    ' PASTE YOUR EXISTING "EDIT CUSTOMER" CODE HERE
    Dim rng As Range
    Set rng = Selection
    
    If rng.Cells.Count > 1 Then
        MsgBox "Please select a single customer cell.", vbExclamation
        Exit Sub
    End If
    
    If rng.Row < 2 Then
        MsgBox "Please select a customer row.", vbExclamation
        Exit Sub
    End If
    
    ' Your edit logic here
    Dim newValue As String
    newValue = InputBox("Enter new value:", "Edit Customer", rng.Value)
    
    If newValue <> "" Then
        rng.Value = newValue
        MsgBox "Customer updated!", vbInformation
    End If
End Sub

Public Sub CRM_ViewAll()
    ' PASTE YOUR EXISTING "VIEW" CODE HERE
    Sheets("Customers").Activate
    Range("A1").Select
End Sub

Public Sub CRM_Reports()
    ' PASTE YOUR EXISTING "REPORTS" CODE HERE
    MsgBox "Generating CRM reports..." & vbCrLf & _
           "This feature will be available in the next update.", _
           vbInformation, "Reports"
End Sub

' =============================================
' KEEP YOUR EXISTING EVENT CODE (IT STILL WORKS IN EXCLUSIVE MODE!)
' =============================================

' Your original Worksheet_Change events remain exactly as they are
' They'll fire automatically when you're in exclusive mode
' They'll be safely ignored in shared mode (no errors, just won't fire)

Private Sub Worksheet_Change(ByVal Target As Range)
    ' YOUR ORIGINAL EVENT CODE - UNCHANGED
    ' This automatically runs when you're the only user
    ' Does nothing in shared mode (Excel disables it)
    
    ' Example - replace with your actual CRM logic
    If Not Intersect(Target, Range("A:A")) Is Nothing Then
        If Target.Row > 1 Then
            ' Auto-timestamp when customer name changes
            Target.Offset(0, 1).Value = Date
            Target.Offset(0, 2).Value = Environ("Username")
        End If
    End If
End Sub

Installation Instructions

Step 1: Open your CRM file
Step 2: Press Alt + F11 to open VBA
Step 3: Double-click "ThisWorkbook" in Project Explorer
Step 4: Paste the ENTIRE code above
Step 5: Press Ctrl + S to save
Step 6: Close and reopen the file

What This Gives...

The One-Minute User Training

CRM Quick Guide:

• Blue toolbar at top? = Multiple users editing. Click buttons to update CRM.
• No toolbar? = You're alone. Automatic updates work like always.
• Simple rule: See toolbar → use buttons. No toolbar → type normally.

Look, I know you want your automatic events back. But here's the reality: Excel was never designed to have two people triggering VBA events simultaneously in the same file. It's like two drivers both trying to control the same car.

My answers are voluntary and without guarantee!

Hope this will help you.

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