Outlook Attachment Preview Error: This file cannot be previewed Ranjan.info

Attachment file preview suddenly stopped working in my desktop Outlook app. When selecting an attachment file (PDF, XLSX or DOCX), an error appears in the Outlook preview window:

This file cannot be previewed because there is no previewer installed for it.


This file cannot be previewed because the following previewer has been disabled.
This file cannot be previewed because of an error with the following previewer: Microsoft Excel previewer.

Outlook: This file cannot be previewed

Let us see how to fix Outlook preview issue on Windows 10/11.

First, make sure you have an app installed on your computer to view this file type. For example, Adobe Reader for PDF or Microsoft Excel for XLSX files. Also, note that the bitness of the Outlook and Viewer apps must match. For example, if you have 32-bit Outlook and Adobe Reader x64, you will not be able to preview PDF files in Outlook. Install the correct version of the viewer.

Then check the preview settings in Outlook.

  1. go for file , alternative , trust Center , trust center settings , attachment handling,
  2. Make sure that turn off attachment preview The option is not enabled;
  3. Click Attachment and Document Previewer,
  4. Check that the Viewer app is enabled in the application list for the file types you need; Outlook Check Attachment Previewer's Settings
  5. Then go to the General tab and check optimize for compatibility option in the user interface options. Microsoft Outlook - Customize for Compatibility

Then check the association settings for Preview Programs in the registry. Run regdeit.exe and go to one of the following registry keys depending on your Outlook version:

  • Office 365 to Microsoft Outlook (Microsoft 365 Apps for Enterprise) – HKLM\​SOFTWARE\​Microsoft\​Office\​ClickToRun\​REGISTRY\​MACHINE\​Software\​Microsoft\​Windows\​CurrentVersion\​PreviewHandlers
  • x86 version of Outlook from Office 2021/2019/2016 – HKLM\​SOFTWARE\​Microsoft\​Windows\​CurrentVersion\​PreviewHandlers
  • Outlook x64 – HKLM\​SOFTWARE\​Wow6432Node\​Microsoft\​Windows\​CurrentVersion\​PreviewHandlers

Make sure your registry branch contains the parameters below (each option for a specific file type or app):

registry parameter value
{00020827-0000-0000-C000-000000000046} Microsoft Excel Previewer
{21E17C2F-AD3A-4b89-841F-09CFE02D16B7} Microsoft Visio Previewer
{65235197-874B-4A07-BDC5-E65EA825B718} Microsoft PowerPoint Previewer
{84F66100-FF7C-4fb4-B0C0-02CD7FB668FE} microsoft word previewer
{DC6EFB56-9CFA-464D-8880-44885D7DC193} Adobe PDF Preview Handler for Vista

If one of these parameters is missing in the registry key, create it manually ( REG_NO type).

If you have a REG_EXPAND_SZ parameter with the specified ID @%CommonProgramFiles%\Microsoft Shared\Office16\oregres.dll,-403remove it

In my case, I had the following item:

{00020827-0000-0000-C000-000000000046} = @%CommonProgramFiles%\Microsoft Shared\Office16\oregres.dll,-403

I removed it and created a new REG_SZ parameter:

{21E17C2F-AD3A-4b89-841F-09CFE02D16B7} = Microsoft Visio previewer

After that, the Excel file preview works fine in Outlook.

If you can’t preview PDF files in Outlook using Adobe Acrobat Reader (in this particular app!), check that AppID , {534A1E02-D58F-44f0-B58B-36CBED287C7C} is present in the parameter HKLM\SOFTWARE\WOW6432Node\Classes\CLSID\{DC6EFB56-9CFA-464D-8880-44885D7DC193} registry key.

If PowerToys is installed on the computer, make sure that Enable PDF preview option is disabled in its settings (in the File Explorer Add-ons section)

Disable PDF Preview in PowerToys

If nothing helps, try both programs (both Outlook and the Viewer app).

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