List file names in folder

[Temporary-Failure]

I have folder that includes thousands pdf-files. They are numbered like
14500.pdf
.
.
15666 invoice.pdf
.
.
23000 list.pdf

and so on.

I need macro which takes bigest number+1 of the file name and puts it in cell A1 (in this situation it should be 23001). I have macro which does this but problem is that it gets slower and slower every day because more files are coming every day. Is there any solution?

[shg]

Please take a few minutes to read the forum rules about cross-posting.

[MaczaQ]

i don't know if it will be solution for you but try this:

Function GreatFileNO(ByVal path As String) As String
    Set d = CreateObject("scripting.filesystemobject").getfolder(path).Files
    
     For Each f In d
        tmp = f.Name
     Next f
     
     GreatFileNO = tmp
    Set d = Nothing
End Function