Path Too Long Error Message When Exceeding MAX_PATH

• Microsoft Windows NT Workstation versions 3.51 and 4.0
• Microsoft Windows NT Server versions 3.51 and 4.0

SYMPTOM

Windows 95 and Windows NT 4.0 clients can expand a server directory structure beyond MAX_PATH (256 characters) by accessing a server share and creating directories and files through the network.

As a result, a server running Windows NT 4.0 will return the following error message if the server administrator tries to access these files or directories locally on the server through Windows NT Explorer:

   Can’t access this folder.
   Path is too long.

   Unable to create the folder '<name>'.
   The filename or extension is too long.

Several tools and programs may also show problems when working with this directory structure that exceeds MAX_PATH.

CAUSE

Win32 programs are limited to a 256-character string size limit because of the MAX_PATH variable. Software programs can work around this problem by passing Win32 a path that is MAX_PATH or less. The real underlying path can then be accessed independently of the real length of the path. In this way, a program can access files or directories beyond MAX_PATH on the server.

RESOLUTION

To resolve problems when the directory structure exceeds MAX_PATH, use either of the following methods:

• On the server that contains the long directory structure, access these files and directories through a local redirection ("net use") of the same share the network clients access across the network.

  -or-

• In Windows NT Explorer, select the folder one level above the folder that returns the error. Right-click the folder returning the error and select Rename. Rename the folder to reduce the number of characters used in the folder name.

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The problem described above could not be reproduced with NTBACKUP and files and directories that were beyond the MAX_PATH limit could be backed up and restored successfully.