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Message “Unable to start PHYLock for drive [n]: … You may need to reduce the cache size.” Appears when Attempting to Backup a Partition

To correct this problem, decrease the value of RAM Cache Size (KB) found on the Image for Windows settings dialog or, if desired, configure Windows to allow a larger non-paged memory pool and/or quota.

Configure the Non-Paged Memory Pool

The non-paged memory pool is not used by normal programs; it is used by drivers and applications when paged memory cannot be used.  Memory that is not part of the non-paged pool is part of the paged pool that normal programs use.  Therefore, you can waste memory by making the NonPagedPoolSize too large.

On the other hand, making the NonPagedPoolSize too small can cause the operating system to halt during startup.  If that were to happen, you would need to revert to the last known good configuration [F8]. 

The default value for NonPagedPoolSize and NonPagedPoolQuota are each 0, which allows Windows to decide what sizes to use.

IMPORTANT: The instructions below contain information on modifying the registry.  Before you modify the registry, you should back it up and understand how to restore it if a problem occurs.  For more information, see:

256986 Windows registry information for advanced users

To change the size of the Windows non-paged pool and/or quota:

  1. Start the Registry Editor.

  2. Navigate to the following key:

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

  3. Change the value named NonPagedPoolSize to the number of bytes to allocate for the non-paged memory pool.

  4. Change the value named NonPagedPoolQuota to the maximum number of megabytes a single program (process) can allocate from the non-paged memory pool.  Valid values are from 0 to 128.

  5. Reboot for the new values to take effect.

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