How to detect if all checkboxes are disabled?

Solution 1:

Exit the loop as soon as you find an enabled checkbox:

Dim Args As Variant
Dim i As Integer
Dim ctl As Control
Dim bCheck As Boolean

bCheck = False

If Not IsNull(Me.OpenArgs) Then
    Args = Split(Me.OpenArgs, ";")
        Me.txtForm = Args(0)
        Me.lblChoices.Caption = Args(1)
End If

For Each ctl In Forms(Me.Name).Controls
    If ctl.ControlType = acCheckBox Then
        ctl.Value = False
        If ctl.Enabled Then
            bCheck = True
            Exit For 'stop checking
        End If
    End If
Next

If bCheck Then
    fncMsgBox "Labor has been entered for all bundles on this step."
    DoCmd.Close acForm, Me.Name
End If

Note: you don't need = True in your If when the value you're checking already represents a boolean.