Office Online and FAST Search Document Thumbnail and Preview Scenarios


You may find that Document Previews and Thumbnails are not shown in FAST search results for SharePoint 2010.


There are many scenarios which could prevent Document Thumbnails and Previews from being displayed in search results. This article will list many scenarios and troubleshooting steps that can be used to help identify known issues that could prevent Thumbnails and Previews from being displayed within Search Results.


To resolve this problem you can utilize the following list as guidance while troubleshooting “Document Thumbnails and Previews” issues with Fast Search Server 2010 for SharePoint.

1. Is Office Online is installed and working on SharePoint Farm?

To support the previews in Fast search results, you need to install Office Online on all the SharePoint servers in the farm. Please see the following articles for more information

Office Online Install Validation:

After installing Office Online and running the SharePoint 2010 Products Configuration Wizard, there will be a service application available for the PowerPoint and Word file formats of .pptx and .docx. Open Central Administration and go to Manage Service Applications. There will services for PowerPoint and a Word viewing service application listed. Click on the service application to check the configuration.

Testing 'View in browser' feature:

a. Browse to a SharePoint site document library hosting Office files of .pptx and .docx format.

b. Within the document library, click on a PowerPoint or Word file and the file should open in the browser. Or you can select the dropdown arrow next to the file, and choose from the menu "view in browser” to test Word or PowerPoint web app functionality.

2. Has the Content Source been re-crawled after Office Online was installed and verified?

After installing Office Online, you need to re-crawl all content to populate the required serverredirectedurlfield for indexed content.

3. If you have customized your Fetched Properties (Search Core Results Web Part -> Display Properties -> Use Location Visualization unchecked) confirm that the properties sitename, fileextension and serverredirectedurl are present. Those are mandatory properties for the Thumbnail and Preview to work.

4. Confirm that the managed property “serverredirectedurl” field contains the correct value.

You can utilize the Fast Search QRServer to retrieve the value from the "serverredirectedurl" field. The value of the "serverredirectedurl" field should
 be working and accessible. This can be tested by pasting the value into a web browser. The document should correctly render and be displayed.

FIELD NAME="serverredirectedurl"></FIELD>

5. Check the SharePoint ULS logs on the server running SharePoint Search Service for information related to ”wacproxy”.

By default the ULS logs are written to "C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\14\LOGS".

6. Utilize an HTTP Debugger to validate that the wacproxy.ashx requests have "HTTP Status: 200".

The request to wacproxy.ashx may return the following:

Bad response example:

parent.window['DelegateFn_SRB_g_3a30f0ed_aa28_455d_8bf4_099fc3b9a46d_1']('ERROR:603:WebException - The remote server returned an error: (401) Unauthorized.');

Good response example:
parent.window['DelegateFn_SRB_g_3a30f0ed_aa28_455d_8bf4_099fc3b9a46d_1']('{"images": ["]});

7. Verify that Document Previews and Thumbnails are enabled in the core results web part on the Fast Search result page. 

To verify:
a. Navigate to the SharePoint Search site and perform a search.
b. Once results are displayed choose "Site Actions", then "Edit Page".
c. Locate the "Search Core Results" Web Part.
d. Edit Web Part.
e. Expand "Display Properties"
f. Ensure that both "Enable Document Preview For PowerPoint" and Enable Thumbnail Preview For Word" are selected.

8. Validate that "Word Viewing Service", "Word Viewing Service Application Proxy", "PowerPoint Service Application", and "PowerPoint Service Application Proxy" are associated to the web application.

To verify:

a. Go to SharePoint Central Administration.
b. Choose "Application Management".
c. Open "Configure Service Application Associations".
d. Ensure that the "Word Viewing Service", "Word Viewing Service Application Proxy", "PowerPoint Service Application", and "PowerPoint Service Application Proxy" Application Proxies are enabled for the web application hosting the search site.

9. If the search site is using HTTPS, ensure that the following required fix is installed:

The Document Preview over SSL issue was addressed in the following update:
Description of the SharePoint Server 2010 Cumulative Update Server Hotfix Package (MOSS server-package): December 31, 2010

Note: If SSL is being used, you must add the correct root certificate and all intermediate certificates in the chain to the SharePoint Trust Relationships configuration:

SharePoint Central Administration\Security\Trust Relationships

10. Confirm if a Network Load Balancer (NLB) device is being utilized in the SharePoint Farm. When utilizing a Network Load Balancer (NLB) with FAST Search, "Source Persistence" is required to allow the wacproxy redirect to successfully re-authenticate with the FAST Server. If the wacproxy redirect utilizes a different SharePoint Front-End Server, document previews and thumbnails within search results will not be displayed.

If an NLB device is being used, you can by-pass the NLB from the Front End SharePoint Servers by modifying the HOSTS file on those systems.

Example: nlbcluster

In the above example, is the IP Address for a SharePoint Front End and the name is the NLB Cluster name. This test will force network connectivity going to to stay on SharePoint Front End server, thus by-passing the NLB device.

If this workaround allows Document Thumbnails and Previews to be displayed, you should look further into the NLB configuration for a permanent resolution.

If F5 Big-IP Load Balancers are being utilized, review the Microsoft FAST Search Server 2010 (BIG-IP LTM v10.2.x, v11) Deployment Guide for more information.

11. This problem may be a result of security update MS08-068:

Known issues with this security update
After you apply this security update, applications such as Microsoft SQL Server or Internet Information Services (IIS) may fail when they make local NTLM authentication requests.
This problem occurs because of the way that NT LAN Manager (NTLM) treats different naming conventions as remote entities instead of as local entities. A local authentication failure might occur when the client calculates and caches the correct response to the NTLM challenge that is sent by the server in local "lsass" memory before the response is sent back to the server. When the server code for NTLM finds the received response in the local "lsass" cache, the code does not honor the authentication request and treats it as a replay attack. This behavior leads to a local authentication failure.
Configure registry key to DisableLoopbackCheck on both SharePoint Front End Servers.
To set the DisableLoopbackCheck  registry key, follow these steps:

a. Click Start, click Run, type regedit, and then click OK.

b. In Registry Editor, locate and then click the following registry key:
c. Right-click Lsa, point to New, and then click DWORD Value.

d. Type DisableLoopbackCheck, and then press ENTER.

e. Right-click DisableLoopbackCheck, and then click Modify.

f. In the Value data box, type 1, and then click OK.

g. Quit Registry Editor, and then restart the server.

12. Is the SharePoint Search Site using Claims Based Authentication?

Document Previews do not work with Claims Based Authentication and is a known limitation with the Product.

For more information see the KB Article Document Previews not available with Claims Based Authentication

More Information

The following is a list of articles and resources listed throughout this article for reference:

ULS Viewer -

Description of the SharePoint Server 2010 Cumulative Update Server Hotfix Package (MOSS server-package): December 31, 2010

How to use a Hosts file to test a site that uses host headers on an Intranet -

You receive error 401.1 when you browse a Web site that uses Integrated Authentication and is hosted on IIS 5.1 or a later version

MS08-068: Vulnerability in SMB could allow remote code execution -

Document Previews not available with Claims Based Authentication -


Artikelnummer: 2554903 – Letzte Überarbeitung: 17.04.2014 – Revision: 1