Recovering a vast number of files from a file backup

Applies to: Microsoft Windows Server 2003

When recovering a very large number of files at a time (hundreds of thousands or millions) from a file backup, you might encounter the following problem:

  • The recovery process fails, and the message “Error reading the file” appears.
  • Not all of the files are recovered.

The most likely cause of the problem is an insufficient amount of memory allocated to the recovery process by the operating system’s cache manager. You can either work around this problem or modify the registry to increase the amount of allocated memory, as described below.

To resolve the problem, do either of the following:

  • Recover the files as two or more groups. For example, if the problem occurs when recovering 1 million files, try recovering the first 500,000 of them and then the remaining 500,000.
  • Modify the registry as follows:

    Note: This procedure requires restarting the machine. Use standard precautions when modifying the registry.

    1. In Registry Editor, open the following registry subkey:

      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

    2. Add the PoolUsageMaximum entry to the subkey:
      • Entry type: DWORD Value
      • Base: Decimal
      • Value: 40
    3. Add the PagedPoolSize entry to the subkey:
      • Entry type: DWORD Value
      • Base: Hexadecimal
      • Value: FFFFFFFF
    4. Quit Registry Editor, and then restart the machine.

    If this does not resolve the problem, or for more details on adding these registry settings, see the corresponding Microsoft Help and Support article.

Tip: In general, if a volume contains many files, consider using a disk-level backup instead of a file-level one. In this case, you will be able to recover the entire volume as well as particular files stored on it.

Recovering a vast number of files from a file backup