Ensure Excel file is not being used before opening using VBA - excel

Question

I am using an interface made with Excel to allow users to concurrently edit a shared data file. To prevent multiple users from editing at the same time I made the following function to do the following:
Open the file
If the file was opened as a read-only, close the file and re-open until the file is opened as read-write or the maximum number of allowed attempts is crossed.
Function OpenTillCanEditC(refpath As String, pw As String) As Workbook
Dim wbtoopen As Workbook
Dim maxOpen As Long
Dim i As Long
Dim buttonClicked As Long
maxOpen = 10
i = 0
On Error GoTo ErrHandler:
Application.DisplayAlerts = False
Set wbtoopen = Workbooks.Open(refpath, True, Password:=pw, ReadOnly:=False)
Application.DisplayAlerts = True
While wbtoopen.ReadOnly And i < maxOpen
If wbtoopen.ReadOnly Then
wbtoopen.Close (False)
Application.Wait (Now + TimeValue("00:00:01"))
Set wbtoopen = Nothing
i = i + 1
If i >= maxOpen Then
buttonClicked = MsgBox("It appears the masterlist is currently being used by someone else. Do you want to retry opening?", vbRetryCancel)
If buttonClicked = vbRetry Then
maxOpen = maxOpen + 10
Application.DisplayAlerts = False
Set wbtoopen = Workbooks.Open(refpath, True, Password:=pw, ReadOnly:=False)
Application.DisplayAlerts = True
End If
Else
On Error GoTo ErrHandler:
Application.DisplayAlerts = False
Set wbtoopen = Workbooks.Open(refpath, True, Password:=pw, ReadOnly:=False)
Application.DisplayAlerts = True
End If
End If
Wend
Set OpenTillCanEditC = wbtoopen
Exit Function
ErrHandler:
Application.DisplayAlerts = True
If Err.Number = 1004 Then
MsgBox "The password keyed in is wrong."
Else
MsgBox "The masterlist found in " & refpath & " cannot be opened. It may be used by someone else or corrupted. If corrupted please open the file manually using Excel."
End If
Set wbtoopen = Nothing
Set OpenTillCanEditC = wbtoopen
End Function
OpenTillCanEditC will be used in a sub for updating as shown below:
Sub UpdateFile()
'Try to open
Dim datawb As Workbook
Dim filepath As String
Dim pw As String
filepath = "C:\Folder Containing File\Data File.xlsx"
pw = "password"
Set datawb = OpenTillCanEditC(filepath, pw)
If datawb Is Nothing Then
MsgBox "File cannot be opened or is currently in use."
Exit Sub
End If
'Do functions needed in the workbook here
datawb.Save()
datawb.Close
End Sub
However I keep getting either of the following two errors:
When multiple people are attempting to access the file, the OpenTillCanEditC function will still ask for a password even though it is already being keyed in.
datawb.Save() will sometimes throw an error stating that the save failed due to multiple users accessing the file.
How do I fix both of these issues to allow multiple users to edit a shared password-protected file using VBA?