VBA: excel is closing, no error generated - vba

Question

I have a macro which I run on many file. The goal is to define a source and copy the value inside my file. It works fine for 30 source files but I recently have one that makes my excel crash, no error message nothing.
Here the code:
'dimensioning of the variables
'range and workbook
Dim Target_Area As Range
Dim Account_Number, Account_Description, Debit, Credit As Range
Dim General_Balance As Workbook
Dim Transform_file As Workbook
Dim Source_Range As Range
'technical var
Dim LastCell As Range
Dim LastCellNumber As Long
Dim Array_Position As Integer
Dim Worksheet_general_balance As Long
Dim Links As Variant
Dim address As String
'var used to adapt to the different trial balance
Dim startline, account_column, description_column, debit_column, credit_column As Integer
Dim column_to_test As String
Dim Target_Column(0 To 3) As Integer
'setting the variables
address = "blabla"
startline = 5
account_column = 1
description_column = 2
debit_column = 3
credit_column = 4
column_to_test = "A"
Target_Column(0) = 1
Target_Column(1) = 4
Target_Column(2) = 5
Target_Column(3) = 6
Worksheet_general_balance = 1
Set Transform_file = ActiveWorkbook
Set General_Balance = Workbooks.Open(address)
With General_Balance.Worksheets(Worksheet_general_balance)
Set LastCell = .Cells(.Rows.Count, column_to_test).End(xlUp)
LastCellNumber = LastCell.Row
End With
MsgBox "General TB sheet name: " & General_Balance.Worksheets(Worksheet_general_balance).Name
'3. save the required range from the source file
General_Balance.Worksheets(Worksheet_general_balance).Activate
Set Account_Number = General_Balance.Worksheets(Worksheet_general_balance).Range(Cells(startline, account_column), Cells(LastCellNumber, account_column))
Set Account_Description = General_Balance.Worksheets(Worksheet_general_balance).Range(Cells(startline, description_column), Cells(LastCellNumber, description_column))
Set Debit = General_Balance.Worksheets(Worksheet_general_balance).Range(Cells(startline, debit_column), Cells(LastCellNumber, debit_column))
Set Credit = General_Balance.Worksheets(Worksheet_general_balance).Range(Cells(startline, credit_column), Cells(LastCellNumber, credit_column))
'copying the value to the file
Transform_file.Activate
Transform_file.Worksheets("general balance").Range(Cells(6, Target_Column(0)), Cells(LastCellNumber - startline + 6, Target_Column(0))).Value = Account_Number.Value
Transform_file.Worksheets("general balance").Range(Cells(6, Target_Column(1)), Cells(LastCellNumber - startline + 6, Target_Column(1))).Value = Account_Description.Value
'up to this point, everything works well
'THE FOLLOWING TWO LINES EITHER ONE OF THEM MAKE EXCEL CRASH
Transform_file.Worksheets("general balance").Range(Cells(6, Target_Column(2)), Cells(LastCellNumber - startline + 6, Target_Column(2))).Value = Debit.Value
Transform_file.Worksheets("general balance").Range(Cells(6, Target_Column(3)), Cells(LastCellNumber - startline + 6, Target_Column(3))).Value = Credit.Value
General_Balance.Close
If I replace the range name Debit or Credit by Account_Number for example, the macro will finish, so i guess it's not about the destination.
I tried to put this code:
For Each cell In Debit.Cells
MsgBox cell.Value
Next cell
Before the problematic lines, and it goes through all the cells without any problems.
I can't find any reason why it's not working... any idea ?

Answer 1

First I think you should add some On Error to your code, including a
MsgBox Err.Description,,Err.Number.
My first guess is that you are trying to write to an already open/locked file.
Sub test()
On Error GoTo Hell
'Do lots of things
'...
Adios:
Exit Sub
Hell:
MsgBox Err.Description, vbCritical, "Error " & Err.Number
Resume Adios
Resume
End Sub
With the above sample, when you get the message box, press Ctrl+Break, move the yellow dot from the resume Adios to the Resume line, then press F8. Now you are on the line that caused the error.
Another way is to start your Sub in debug mode, and press F8 until it crashes (and remember where that was !).