File May Be Truncated to Zero Bytes When Copied Onto Itself (138014)

SYMPTOMS

When you try to copy a file onto itself, you receive a Confirm File Replace dialog box prompting you to confirm that you want to replace the existing file. If you click Yes, the file may be truncated to zero bytes. If you click No, the file is unchanged.

This problem occurs only when you copy a file onto itself using two different views of the same network resource (such as when you have two different drive letters mapped to the same network resource, or when you have two UNC connections to the same network resource), or when you copy a file onto itself using a drive created with the SUBST command.

NOTE: If you try to move (rather than copy) a file in this manner, the file may be deleted.

RESOLUTION

This issue is resolved by the following updated file for Windows 95, and later versions of this file:

   SHELL32.DLL  version 4.00.951  817,664 bytes

To install this update, download the Windows 95 Service Pack 1 Update Setup.exe file from one of the sources listed below.

In addition to correcting the problem described in this article, the new version of Shell32.dll provides the ability to browse printers from the Add Printer Wizard for users of the Microsoft Service for NetWare Directory Services (NDS). Users of the standard network clients included with Windows 95 can already browse printers and do not require this update to browse for printers.

Installation

To correct the problem described in this article, follow these steps:

Download the Setup.exe file from one of the online services listed below to an empty folder.
In My Computer or Windows Explorer, double-click the Setup.exe file.
Follow the instructions on your screen.
After the installation process is finished, shut down and then restart your computer.

Instructions for Downloading

To obtain this file, apply Microsoft Windows 95 Service Pack 1. For additional information about applying Microsoft Windows 95 Service Pack 1, click the article number below to view the article in the Microsoft Knowledge Base:

142794 Availability of Microsoft Windows 95 Service Pack 1

MORE INFORMATION

This problem does not affect most users, because copying a file onto itself is an unnecessary task. In addition, this problem occurs only in the following circumstances:

The problem occurs only when you copy a file onto itself on a drive using drive mapping (such as a mapped network drive or a drive created with the SUBST command) or a UNC connection. Users in non-networked environments, and users who do not use the SUBST command, are not affected by this problem.
The problem occurs only if you use two views of the same network resource, or drive created with the SUBST command, and copy a file onto itself. For example, the problem may occur if you map drive X to the \\<server>\<folder> network resource, map drive Y to the same network resource, and then copy a file from the root folder of drive X to the root folder of drive Y.
The problem occurs only with files of a certain size. While preliminary testing indicates that only files smaller in size than approximately 234K are affected, the affected file size is also dependent on the size of the local and network buffers, and may vary based on configuration.

For additional information about issues resolved by updates to this component, please see the following articles in the Microsoft Knowledge Base:

161100 File May Be Truncated When Copied to a Full Network Drive

150215 Disabling Automatic Network Shortcut Resolution

138014 File May Be Truncated to Zero Bytes When Copied Onto Itself

136834 Error Copying Read-Only Files to Core SMB Server

160807 Cannot Connect to Windows NT Server with Many Shares

For additional information about Windows 95 updates, please see the following article in the Microsoft Knowledge Base:

161020 Implementing Windows 95 Updates