Access files with long paths (over 260)

Question

I'm using Microsoft Scripting Runtime (FSO) to parse folders and produce a list of all of its contents, the folders are on a network and resultant paths end up longer than 260. The minimum code I have is as below:-

Private Sub ProcessFolder(ByVal StrFolder As String)
Dim Fl              As File
Dim Fldr            As Folder
Dim RootFldr        As Folder

Set RootFldr = FS.GetFolder(StrFolder)

    For Each Fl In RootFldr.Files
        Debug.Print Fl.Path
    Next

    For Each Fldr In RootFldr.SubFolders
        DoEvents
        ProcessFolder Fldr.Path
    Next

Set RootFldr = nothing    
End sub

At a certain level StrFolder length became 259, the Set RootFldr ... folder line worked but For Each Fl In RootFldr.Files gave the error of 76: Path not found, presumably because the content causes the path to breach the 260 limit.

There were files in the folder when looking in Windows Explorer. I am using Excel as the host for this code as I'm outputting the result to workbooks.

Just to be super clear on my question and its background, I need to use FSO (happy to be shown alternatives if they exist) to access files deeper than 260 characters deep in their network path. I need it as FSO as the tool I have is taking the folder paths and the file paths, name, size created, and modified.

Answer 1

The technique to convert MAXFILE encumbered DOS path names to native OS path names is well established and documented. Summarizing:

• Prefix a path that uses a drive letter with \\?\, like \\?\C:\foo\bar\baz.txt
• Prefix a path that uses a file share with '\\?\UNC\, like \\?\UNC\server\share\baz.txt.

Works well with FileSystemObject too, at least when I tested your code on Windows 10. That might not necessarily be the case in older Windows versions or with the network redirector on your server. Tested by using the FAR file manager to create subdirectories with long names and verified with:

Dim path = "\\?\C:\temp\LongNameTest"
ProcessFolder path

Produced:

\\?\c:\temp\LongNameTest\VeryLongFolderName0123456789012345678901234567890123456789012345678901234567890123456789\VeryLongFolderName0123456789012345678901234567890123456789012345678901234567890123456789\VeryLongFolderName0123456789012345678901234567890123456789012345678901234567890123456789\VeryLongFolderName0123456789012345678901234567890123456789012345678901234567890123456789\VeryLongFolderName0123456789012345678901234567890123456789012345678901234567890123456789\Chrysanthemum.jpg

Which is 488 characters long. Things to keep in mind:

• Native path names must be full paths, they cannot be relative paths. In other words, they must always start with a drive letter or share name and start from the root of the drive/share.
• You get the native path name back, don't forget to strip the prefix off again if you display it.
• Not tested but should fail, there is still a limitation on the the length of the filename itself (without the directory names), can't be longer than 259 chars. Shouldn't be a problem at all since the user can't create them either.