Symptoms
Assume that you run an application to convert a video file to the Advanced Systems Format (ASF) on a Windows RT, Windows 8, or Windows Server 2012-based computer. When Windows Explorer generates the thumbnail image from the ASF file, the Dllhost.exe process consumes excessive CPU resources.
Cause
This issue occurs because the index object in the ASF file is corrupted.
Resolution
Update information
To resolve this issue, install update rollup 2855336. For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base:
2855336 Windows RT, Windows 8, and Windows Server 2012 update rollup: July 2013
Status
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
More Information
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates
