Outlook data not Instant Search indexed with malformed NoOST value

Applies to: Outlook 2013Microsoft Outlook 2010


In Microsoft Outlook, you are unable to perform an Instant Search. Instant Search attempts return the following messages:

In Outlook 2010

No matches found for "<search string>".
Try searching again in All Mail Items

Clicking Try searching again in All Mail Items returns

No matches found for "<search string>".

In Outlook 2013

We couldn't find what you were looking for.
Find more on the server.

if your Outlook client is currently connected to Microsoft Exchange Server. If it is working offline, you may receive the following:

No matches found. Search is limited to the last 12 months because the server is unavailable.

Additionally, in both cases, Windows Search Indexing Options may report Indexing complete.


This behavior can occur if the following registry value is configured:

HKEY_CURRENT_USER \Software\Microsoft\Office\x.0\Outlook\OST
Name: NoOST
Type: any type other than REG_DWORD

Where x.0 is 15.0 for Outlook 2013, or 14.0 for Outlook 2010.

The NoOST registry value must be created as a DWORD. If configured incorrectly, Windows Search will fail to index the local Outlook data, resulting in no results returned on search attempts.


Delete the NoOST registry value, and if needed, recreate it as a DWORD, using the steps below.

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

  1. Quit Outlook.
  2. Launch the Registry Editor using the appropriate steps below.

    Windows 7

    From the Start menu, click Run, type regedit in the Open box, and then click OK.

    Windows 8/8.1

    From the Start screen, type regedit and press Enter.
  3. Locate and then click to select the following registry key:

    HKEY_CURRENT_USER \Software\Microsoft\Office\x.0\Outlook\OST

    Where x.0 is 15.0 for Outlook 2013, or 14.0 for Outlook 2010.
  4. Right-click the NoOST value, click Delete, and click Yes to confirm the deletion.
  5. If needed, from the Edit menu click New and click DWORD (32-bit) Value.
  6. Type NoOST and press Enter.
  7. From the File men, click Exit to close the Registry Editor.