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Support for Windows Vista Service Pack 1 (SP1) ended on July 12, 2011. To continue receiving security updates for Windows, make sure you're running Windows Vista with Service Pack 2 (SP2). For more information, refer to this Microsoft web page: Support is ending for some versions of Windows.


You try to download a file that is larger than 50000000 bytes from a Web folder on Windows XP Service Pack 2 (SP2), or a later version of Windows. You may receive an error message that is similar to the following:

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

Note In this error message, FileName is a placeholder for the name of the file.

This problem also occurs on a Windows Vista-based computer or a Windows XP Service Pack 1 (SP1)-based computer that has security update 896426 (MS05-028) installed.

In this scenario on Windows 7, 8, or 8.1, you might receive the following error message:

Copy Folder

An unexpected error is keeping you from copying the folder. If you continue to receive this error, you can use the error code to search for help with this problem.

Error 0x800700DF: The file size exceeds the limit allowed and cannot be saved.

<file name>

Try again Cancel


This issue occurs because a security change that was introduced 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.


Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

322756 How to back up and restore the registry in Windows
If you have Windows XP SP2, Vista, or 7, go to the "Fix it for me" section to run the Fix it. If you prefer to fix this problem yourself, or you are using Windows 8 or 8.1, go to the "Let me fix it myself" section.

Windows XP SP2, Vista, or 7: Fix it for me

To fix this problem automatically, click the Fix it button or link. Then click Run in the File Download dialog box, and follow the steps in the Fix it wizard.

Note This Fix it does not work with Windows 8 or later.


  • When you follow the Fix it wizard, you need enter a FileSizeLimitInBytes value that is larger than the size of the file that you want to download.

  • This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.

  • If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.

Then, go to the "Did this fix the problem?" section.

Let me fix it myself

To resolve this issue, follow these steps:

  1. Windows XP SP2, Vista, or 7: Click Start, click Run, type regedit, and then click OK.

    Windows 8 or later: Swipe in from the right to bring up the charms, and then select Search and type regedit (or type regedit from the Start screen). Select regedit from the search results to run it.

  2. Locate and then click the following registry subkey:


  3. In the right pane, right-click the
    FileSizeLimitInBytes value, and then click

    If you cannot see the
    FileSizeLimitInBytes value, right-click the blank space in the right pane, click New, click DWORD Value, type FileSizeLimitInBytes, and then click

  4. In the Edit DWORD Value box, click to select the Decimal option. In the box under Value data, type a value that is larger than the size of the file that you want to download. Click OK.

    Note The default value for the file size limit is 50000000 bytes.

  5. Quit Registry Editor. Restart the computer.

Did this fix the problem?

  • Check whether the problem is fixed. If the problem is fixed, you are finished with this section. If the problem is not fixed, you can contact support.

  • We would appreciate your feedback. To provide feedback or to report any issues with this solution, please leave a comment on the "Fix it for me" blog or send us an email.

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