Detect whether Excel workbook is already open [closed]

Answer 1

I would go with this:

Public Function FileInUse(sFileName) As Boolean
    On Error Resume Next
    Open sFileName For Binary Access Read Lock Read As #1
    Close #1
    FileInUse = IIf(Err.Number > 0, True, False)
    On Error GoTo 0
End Function

as sFileName you have to provide direct path to the file for example:

Sub Test_Sub()
    myFilePath = "C:\Users\UserName\Desktop\example.xlsx"
    If FileInUse(myFilePath) Then
        MsgBox "File is Opened"
    Else
        MsgBox "File is Closed"
    End If
End Sub