Possible computer performance issues if the UseLowPriorityConfiguration value is set to "0" in the registry

Applies to: Outlook 2013Microsoft Outlook 2010Microsoft Office Outlook 2007

Symptoms


Under some configurations and situations, you may experience random computer performance problems when you have modified the UseLowPriorityConfiguration value in the registry.

Cause


This problem can occur if the following registry data is configured on your computer:

Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search
DWORD: UseLowPriorityConfiguration
Value: 0

Resolution


Set the value of UseLowPriorityConfiguration to 1 (default value) to see whether there is an improvement in performance.

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
  1. Start Registry Editor.
    1. Open the Run box.
      • Windows 8

        Press the Windows key + R
      • Windows 7Windows Vista, or Windows XP

        On the Start menu click Run.

    2. Type Regedit.exe and then click OK.
  2. Locate the following key in the registry:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search
  3. Right-click UseLowPriorityConfiguration and then click Modify.
  4. Change the Value data to 1 and then click OK.
  5. Close Registry Editor.
  6. Restart the Windows Search service.
    1. Open the Run box.
      • Windows 8

        Press the Windows key + R
      • Windows 7, Windows Vista, or Windows XP

        On the Start menu click Run.
    2. Type Services.msc and then click OK.
    3. Right-click the Windows Search service and then click Stop.
    4. Right-click the Windows Search service and then click Start.

More Information


The UseLowPriorityConfiguration registry value can be configured to use either of the following two data values:

1 = (Default) Use low-priority input/output mode for search processes. You do this to keep overall computer performance at an optimum.

0 = Do not use low-priority input/output mode for search processes. There are many factors involved, but using a value of 0 may affect overall computer performance.

We recommend that you do not change the value from the default unless you are provided this guidance from a Microsoft Support Engineer.

There is a different registry value, DisableBackoff, that also controls the way Windows Search indexes items. It can also cause random performance issues if changed from its default value. For more information about the DisableBackoff registry value, please see the following article.

Possible computer performance issues if the DisableBackoff value is set to "1" in the registry
http://support.microsoft.com/kb/2903552