VBA code crashes after saving - says the situation lies with the XML "Run-time error '429' - vba

Question

I made a worksheet for the company I work for to help with pricing out custom designs. A few months ago I made a macro that can save the parts to a text file that can be pulled from at a later date if we wanted to quote out the same design. Everything was working perfectly, until one day I go to open it up and got the error message
We found a problem with some content in 'File.xlsm'. Do you want us to try
to recover as much as we can?
When I click yes, it then comes up with the worksheet the macro was on completely un-formatted and says it could only open the file by repairing or removing the following part
Repaired Part: /xl/worksheets/sheet3.xml part.
This is weird because the only xml code I use is just to create a drop-down menu when the saved design names are loaded. Nothing has changed since the final revision of the code other than the amount of designs that have been saved. The boxes I had as buttons tied to macros have been deleted and none of the code for this sheet works. What it shows when I view the code now is Sheet_Thumbnails
All other macros work, the other sheets are fully functional. When I try and run the code on this sheet I get
Run-time error '429':
ActiveX component can't create object
This has to be when compiling because I can't even debug where this is happening. The best answer I get when I look this error up is that I am not using the "New" keyword when calling a file or object from somewhere else. But I have looked through my code and don't see anywhere that applies. Luckily a co-worker saved a copy off our server to her computer so I have a backup, but when I open this and run the macros then save and re-open, the same crash happens.
Here is the code with xml:
Sub MakeList(ByRef r As Range, ByRef Config As String)
r.Clear
If Not Config = "" Then
r.Select
With Selection.Validation
.Delete
.Add Type:=xlValidateList, AlertStyle:=xlValidAlertStop, Formula1:=Config
.IgnoreBlank = True
.InCellDropdown = True
.InputTitle = ""
.ErrorTitle = ""
.InputMessage = ""
.ErrorMessage = ""
.ShowInput = True
.ShowError = True
End With
End If
End Sub
Can anyone help me? I am at a total loss for why this has happened and why it keeps happening. Is it the validation part? Why would it happen after working for months?
Thank you in advance.
EDIT 1
Exporting all of the code and creating a new workbook did not solve the problem.
Thanks to Profex, the problem has been found and is in the validation. Essentially one of my lists was too long. The formula used in validation is not supposed to be beyond 255 characters. Even though Excel doesn't give any warning on this, when I would create the drop down menus, although it would populate each item from the list, after saving closing and re-opening, apparently this would corrupt the coded sheet. So now the question lies with how to add values into a drop-down menu without clearing and re-initializing with a longer list. Should I post a new question for that?

Answer 1

In Excel, Cell Validation Lists have a 8191 character limit (which is way too long for a user to pick from anyway).
Anything over 254 characters will corrupt the file upon save/re-open.
Here is something similar to what I have done in the past to create Dynamic Validations lists:
It uses your MakeList() subroutine, and requires another GetList() function to get the validation list for the specified cell.
Since this code is in the Workbook module, I also added another function called IsSheetTheOneICareAboutWithValidations(). If you use the WorksSheet_SelectionChange Event from in a specific sheet module, this isn't required; but you would have to change the scope of m_ValidationCell and m_ValidationList to be Public.
This code is untested and goes in the ThisWorkbook module:
Option Explicit
Private m_ValidationCell As Excel.Range
Private m_ValidationList As String
Private Sub Workbook_BeforeSave(ByVal SaveAsUI As Boolean, Cancel As Boolean)
If Not m_ValidationCell Is Nothing Then
m_ValidationList = m_ValidationCell.Validation.Value
m_ValidationCell.Validation.Delete
End If
End Sub
Private Sub Workbook_AfterSave(ByVal Success As Boolean)
If m_ValidationList <> vbNullString Then
With m_ValidationCell.Validation
.Add Type:=xlValidateList, Formula1:=ValidationList
End With
m_ValidationList = vbNullString
End If
End Sub
Private Sub Workbook_SheetSelectionChange(ByVal Sh As Object, ByVal Target As Range)
If Not m_ValidationCell Is Nothing Then
m_ValidationCell.Validation.Delete
Set m_ValidationCell = Nothing
End If
If IsSheetTheOneICareAboutWithValidations(Sh) Then
' Since we're changing the Validation each time there is a new Selection;
' It's the Active Cell that matters, not the Target range
' Add a validation list to any cell in column 4, after the header (in row 1).
If ActiveCell.Column = 4 And ActiveCell.Row > 1 Then
List = GetList(ActiveCell)
MakeList ActiveCell, List
' Should probably add this next line to you MakeList() function
Set m_ValidationCell = ActiveCell
End If
End If
End Sub
Private Function GetList(Target As Range) As String
GetList = vbNullString ' or whatever you want
End Function
Private Function IsSheetTheOneICareAboutWithValidations(Sh As Object) As Boolean
IsSheetTheOneICareAboutWithValidations = (Sh.Name = "Pricing")
End Function

Answer 2

Recovery
It looks like you just had a bad save. Sometimes it just corrupts the file and there isn't much you can do, other then hope you have a backup.
Right Click in the Folder > Properties > Previous Versions
If you don't have a backup, it might just help to move everything to a new file.
Create a New Workbook
Select All cells from your first sheet (click above the 1, left of the A)
Press Ctrl+C to Copy
Select All cells in your New Workbook/Sheet
Press Ctrl+V to Paste
Repeat for all Worksheets
On the VB side of things, you can just Drag the Forms/Modules/Classes from the Old file to the New One.
Issue
Did you know that all New Office documents are really just ZIP files...
Go ahead, rename the file to File.xlsm.zip
Inside the file you'll see a folder structure which should have .../xl/worksheets/sheet3.xml
This is what excel is complaining about! That file is either missing or wrong.
Code
I don't know how you're calling Makelist, so I can't verify that the range R that you are passing is valid.
Please remove the Select/Selection from your code. You don't need to select anything in the front end GUI of Excel to access/change the cells. Also you didn't check if R was Nothing.
Sub MakeList(ByRef r As Range, ByRef Config As String)
If Not r Is Nothing then
r.Clear
If Not Config = "" Then
With r.Validation
...
End With
End If
End If
End Sub