Outlook stops previewing pdf files

Daguerre101 

Hello Daguerre101,

You might encounter a problem where Outlook fails to preview pdf files or Office file attachments with the error: "This file cannot be previewed because there is no previewer installed for it." 

However, If the preview works fine and suddenly stops working, you can try the steps below to fix the problem, 

Check Attachment Handling Settings:

• Firstly, In Outlook, navigate to File > Options > Trust Center > Trust Center settings > Attachment Handling
• Now, ensure that the "Turn off Attachment Preview" box is unchecked.
• Then, click the "Attachment and Document Previewers" button.
• Lastly, check if the "PDF Preview Handler" is enabled/ticked in the window list.

• Firstly, locate under File > Options > General for the section User Interface options.
• Now, select the option to Optimize for compatibility.
• Lastly, restart the application.

Note: You must open the application handling the file you are attempting to preview. Suppose you want to preview the .pdf file, open Acrobat reader.

PDF Registry Fix:

• Firstly, select the Start button, then type regedit.
• Now, select and open the Registry Editor.
• Then, navigate to the following location:
  HKEY_LOCAL_MACHINE \ SOFTWARE \ Wow6432Node \ Classes \ CLSID \ {DC6EFB56-9CFA-464D-8880-44885D7DC193}

• Next, open AppID.
• Lastly, change the Value Data to the following, then select OK,
  {534A1E02-D58F-44f0-B58B-36CBED287C7C}

Thus, I hope the above workarounds help you to fix the "Outlook stops previewing pdf files" issue. However, if the issue persists, you can update it here.

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Regards,
Austin_M