Remote System Receiving Error: "Cannot Copy File Name: Cannot Read From the Source File or Disk"

This article describes how to copy and paste files larger than 50000000 bytes from a remote system using a UNC path to a store in the format of \\servername\ViewStor\.

You try to copy and paste a file that is larger than 50000000 bytes from a Web folder on the software Server. The UNC path is in the format of etc. You may receive an error message that is similar to the following:

Cannot Copy FileName: Cannot read from the source file or disk

The ViewStor log in the install directory reports no problem from ViewStor. Further, the copy and paste works from the software server itself, just not from a client machine.

From Microsoft KB 900900:This issue occurs because a security change in Windows XP SP2 affects the Web Distributed Authoring and Versioning (WebDAV) redirector. This security change makes sure that an unauthorized server cannot force a client computer into a denial of service attack. If you try to download a file that is larger than 50000000 bytes, the client computer interprets this download as a denial of service attack. Therefore, the download process stops.

The setup for the software on the software server changes 2 values for the WebClient service to be able to access files larger the 50 million bytes. Under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters there are 2 values that are changed to 0xffffffff, FileSizeLimitInBytes and FileAttributesLimitInBytes. 

These values may have to be modified in the registry of a remote computer accessing the store via UNC path (i.e. \\[ArchiveIQServer]\ViewStor...) to support copy and paste of files larger than 50 MB. After changing these values you will have to reboot the system. 

Please see: for more information.