Path/file error and catastrophic failure after inactivitiy

Added some functionality to a project I am working on and now I'm getting the above error if I leave the project open over night.

I added a userform that allows the user to change the default save directory. Anyone see the problem?

userform code:

Private Sub UserForm_Initialize()
    Dim myString As String
    myString = Range("ctrWorkDir")
    
    If myString = "" Then
        myString = ActiveWorkbook.Path
    End If
    
    dirBox.Text = myString
End Sub

Private Sub editButton_Click()
Dim myString As String
    Me.Hide
    myString = GetFolder(dirBox.Text)
    dirBox.Text = myString
    Me.Show
End Sub


Private Sub saveButton_Click()
Dim myRange As Range
Set myRange = Range("ctrWorkDir")

    
    If Not FolderExists(dirBox.Text) Then
        MsgBox "Invalid folder, try again."
        Exit Sub
    End If
    Me.Hide
    myRange = dirBox.Text
    Load formOptions
    
    With formOptions
      .StartUpPosition = 0
      .Left = Application.Left + (0.5 * Application.Width) - (0.5 * .Width)
      .Top = Application.Top + (0.5 * Application.Height) - (0.5 * .Height)
      .Show
    End With
        
    Unload dirEdit
End Sub


Private Sub cancelButton_Click()
Dim myString As String
myString = Range("ctrWorkDir")

    Me.Hide
    
    If myString = "" Then
        myString = ActiveWorkbook.Path
    End If
    dirBox.Text = myString
    
    Load formOptions
    
    With formOptions
      .StartUpPosition = 0
      .Left = Application.Left + (0.5 * Application.Width) - (0.5 * .Width)
      .Top = Application.Top + (0.5 * Application.Height) - (0.5 * .Height)
      .Show
    End With
    
    Unload dirEdit
End Sub

"folder picker"

Function GetFolder(InitDir As String) As String

Dim fldr As FileDialog
Dim sItem As String
sItem = InitDir

Set fldr = Application.FileDialog(msoFileDialogFolderPicker)

With fldr
    .Title = "Select a Folder"
    .AllowMultiSelect = False
    
    If Right(sItem, 1) <> "\" Then
        sItem = sItem & "\"
    End If

    .InitialFileName = sItem

    If .Show <> -1 Then
        sItem = InitDir
        Else
        sItem = .SelectedItems(1)
    End If
End With

GetFolder = sItem
Set fldr = Nothing

End Function

folder validation

Option Explicit

Private Declare Function PathFileExists Lib "shlwapi" Alias "PathFileExistsA" (ByVal pszPath As String) As Long
Private Declare Function PathIsDirectory Lib "shlwapi" Alias "PathIsDirectoryA" (ByVal pszPath As String) As Long

Public Function FileExists(pstrFile As String) As Boolean
    FileExists = (PathFileExists(pstrFile) = 1)
    If FileExists Then FileExists = (PathIsDirectory(pstrFile) = 0)
End Function

Public Function FolderExists(pstrFolder As String) As Boolean
    FolderExists = (PathFileExists(pstrFolder) = 1)
    If FolderExists Then FolderExists = (PathIsDirectory(pstrFolder) <> 0)
End Function

Thanks in advance!