The problem is you're opening the users file for Output, this Automatically creates a New file, removing all your Users.

Instead of updating the File on every delete and keeping the file in a Textbox,
Why don't you just update the file when the user closes the form.
That way you can skip the entire DelUser Sub Routine and You won't need to keep the file in a Textbox, eg.
Code:
Option Explicit

Private Sub cmdDel_Click()
    Dim I As Integer
    Dim sPass As String
    
    If cboUser.ListIndex < 0 Then Exit Sub 'No Users
    
    If Len(txtPass) = 0 Then
        'make sure there is a password
        MsgBox "Please enter your password.", , "Error"
        Exit Sub
    End If
    
    For I = 1 To 20
        'check to see if the user has to remain
        If Cn.mnuMsg(I).Caption = cboUser Then
            MsgBox "You can't delete this user until all there Msg's have been viewed", , "Error"
            Exit For
        End If
    Next
    If I < 21 Then Exit Sub
    
    'get the user pass from the reg (eww_ secure Not)
    sPass = GetSetting(AppTitle, "Users", cboUser)
    'compare the pWords
    If sPass = txtPass Then
        cboUser.RemoveItem cboUser.ListIndex
        DeleteSetting AppTitle, "Users", cboUser.Text
        MsgBox "User Removed", vbInformation + vbOKOnly, "User Removed"
    Else
        MsgBox "Please re-enter your password", , "Invalid Password"
    End If
End Sub

Private Sub Form_Load()
    'Load the User File
    Dim iFile As Integer
    Dim sUserList As String
    
    iFile = FreeFile
    Open App.Path & "\Users.zan" For Input As iFile
    sUserList = Input(LOF(iFile), iFile)
    Close iFile
    While InStr(sUserList, vbCrLf)
        cboUser.AddItem Left(sUserList, InStr(sUserList, vbCrLf) - 1)
        sUserList = Mid$(sUserList, InStr(sUserList, vbCrLf) + 2)
    Wend
    If Len(sUserList) Then cboUser.AddItem sUserList
    If cboUser.ListCount Then cboUser.ListIndex = 0
    txtPass.PasswordChar = "*"
End Sub

Private Sub Form_Unload(Cancel As Integer)
    'Update the User File
    Dim iFile As Integer
    Dim iIndex As Integer
    
    iFile = FreeFile
    Open App.Path & "\Users.zan" For Output As iFile
    For iIndex = 0 To cboUser.ListCount - 1
        Print #iFile, cboUser.List(iIndex)
    Next
    Close iFile
End Sub

Private Sub cmdCancel_Click()
    Unload Me
End Sub
N.B. If you don't want a User to Type into a Combo, set the Style Property to DropDown List..

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Aaron Young
Analyst Programmer
[email protected]
[email protected]