Preview Handler Association Editor is a tool that makes it easy to edit preview handler registrations for particular extensions. It’s useful too to handle the restriction mentioned above where only one previewer is allowed for each extension. When you have two ore more different preview handlers for a file type, the Preview Handler. The PDF Preview Handler error typically appears when Windows users are trying to preview a file in Outlook. The error description states that the file cannot be previewed because of an error to the previewer. The preview pane can be used to see the contents of a file, such as an Office document, without opening it in an app. Preview handlers show the content of files (ex: text files) in the preview pane. (Look for 'prevhost.exe' or 'Preview Handler Surrogate Host (32 bit)'), then right click it and select 'End Task'. Automatically ending of the task: Killing the the Prevhost.exe process can be automated by copying this text into notepad and saving it with a.bat file extension.
-->This topic explains how to register a preview handler associated with a given data type. For the purposes of illustration, examples in this topic use a .xyz file type. Registration of a preview handler is a standard file association-based registration.
Instructions
![Preview Handler Preview Handler](/uploads/1/1/9/7/119770223/676623092.jpg)
Step 1:
First, a file name extension is associated with a ProgID. The following entry associates the xyzfile ProgID subkey with the .xyz file name extension.
The xyzfile ProgID subkey is stored with the other ProgIDs as shown here:
Each preview handler ProgID subkey contains a subkey named shellex that contains a subkey always named {8895b1c6-b41f-4c1c-a562-0d564250836f}. The presence of that subkey tells the system that the handler is a preview handler.
The default value of the {8895b1c6-b41f-4c1c-a562-0d564250836f} subkey is the class identifier (CLSID) of your handler. An example of the xyzfile ProgID subkey is shown here, associating a handler of CLSID {ec3a629a-a47c-4245-bc78-b4b63d0e3154}.
Step 2:
![Bluebeam preview handler Bluebeam preview handler](/uploads/1/1/9/7/119770223/882181467.png)
Next, add the subkey under CLSID for your preview handler. An example is shown here. An explanation of individual entries follows.
The default value for your subkey (here, {ec3a629a-a47c-4245-bc78-b4b63d0e3154}) is not required or used. However, setting it to a nonlocalized string can help you to debug registration issues.
The minus sign (-101) in the .dll resource in the DisplayName entry exists for legacy reasons. The Icon entry, on the other hand, does not require a minus sign.
The AppID value gives a reference to the AppID of the application associated with the file name extension (stored under HKEY_CLASSES_ROOTAPPID. The value used here—{6d2b5079-2f0b-48dd-ab7f-97cec514d30b}—is the ID of the Prevhost.exe surrogate host. 32-bit preview handlers should use AppID {534A1E02-D58F-44f0-B58B-36CBED287C7C} when installed on 64-bit operating systems.
The entries under the InprocServer32 subkey include a reference back to the file name extension's ProgID subkey as well as an entry for a VersionIndependentProgID.
Step 3:
Finally, the preview handler must be added to the list of all preview handlers. This list is used as an optimization by the system to enumerate all registered preview handlers for display purposes. Again, the default value is not required, it simply aids in the debugging process.
Preview Handler Fix Tool
Note
Preview Handler Surrogate Host Outlook
In Windows 7, if the application is installed for all users of the computer, use HKEY_LOCAL_MACHINE; if for only one user, use HKEY_CURRENT_USER.