Check If a File Is Already Open
http://www.vbaexpress.com/kb/getarticle.php?kb_id=468
Untested

Details

Function IsFileOpen(FileName As String)
    Dim iFilenum As Long
    Dim iErr As Long
    
    On Error Resume Next
    iFilenum = FreeFile()
    Open FileName For Input Lock Read As #iFilenum
    Close iFilenum
    iErr = Err
    On Error GoTo 0
    
    Select Case iErr
    Case 0:    IsFileOpen = False
    Case 70:   IsFileOpen = True
    Case Else: Error iErr
    End Select
    
End Function
Copy

Details

Sub test()
    If Not IsFileOpen("C:\MyTest\volker2.xls") Then
        Workbooks.Open "C:\MyTest\volker2.xls"
    End If
End Sub
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check if a folder is open (vba)
Untested

Details

Sub test1()
        Dim OpenFold As Variant
        Dim oShell As Object
        Dim Wnd As Object
        Dim strFolder

        OpenFold = "mysubfolder"
        strFolder = "U:\myfolder\" & OpenFold
        Set oShell = CreateObject("Shell.Application")

        For Each Wnd In oShell.Windows
            If Wnd.Name = "Windows Explorer" Then
               If Wnd.Document.Folder.Self.Path = strFolder Then Exit Sub
            End If
        Next Wnd
        Application.ThisWorkbook.FollowHyperlink Address:=strFolder, NewWindow:=True
End Sub
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Source: https://stackoverflow.com/a/17097610

Alex. Thank you. The sub sent checks for a "myFile.ext" This I get.

I am looking to find if a File Folder is open on the desktop NOT a File.
This to check if  c:\...mydesktop\myFolder\ is open on the desktop.  (Folder It must exist)
The question is if the folder is already opened on the desktop.

Alex has supplied code for both Files AND Folders.

I saw the stack overflow which addresses if an Application s open.

to be precise I have a folder:
C:\Users\Benai\Desktop\EdasduardoBenaim

I need to check if it is open or closed.
If closed I will open it, If closed I don't need to open an other instance

Thank you Alex.
can you point me in this direction.  
I checked the code vault but did not see it

Do you remember a lesson , template or course where this is?

I remember checking if a Folder Exists, but not if is Open

Access Developer 30
Classic VB File I/O. Reading & Writing Text Files

Thank you Alex. I tested your code
In my Computer:
1    Wnd.Name = "File Explorer"
2    Application.ThisWorkbook.FollowHyperlink Address:=strFolder, NewWindow:=True
what would be ThisWorkbook?

The Code is checking if the Directory Exists.
I need to check if it is Open in the Desktop
What am I missing??

ThisWorkbook usually related to Excel. You'll probably need to update accordingly.

Did you update OpenFold and strFolder?

Eduardo Benaim I've had questions similar to this on my to-do TechHelp list forever. I'll bump them up the list.

Alex - thanks for the code. I tested and verified that they work (with some minor tweaks). Adding to the Code Vault soon.