File Explorer not previewing pdf files since 25H2 update

Paul Nicholson 560 Reputation points
2025-10-15T08:07:37.1033333+00:00

Since installing the 25H2 update to Windows 11, the preview for pdf files is not working.

I just get the following message "The file you are attempting to preview could harm your computer. If you trust the file and the source you received it from, open it to view its contents"

I have tried everything to restore the preview without success.

Any help would be much appreciated!

Windows for home | Windows 11 | Files, folders, and storage
Answer recommended by moderator
Vivekanandan Tiwari 210 Reputation points
2025-10-20T03:18:02.11+00:00

Here is a simple solution that worked for me -

in the file explorer, just disable this check box as shown in the image, this simply worked for me

(This happened on windows 10 as well!)
Screenshot 2025-10-20 084655

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  1. Sue S 15 Reputation points
    2025-12-17T20:33:34.7733333+00:00

    This was the intent of Windows, and according to the IT department for my organization, they have no intentions of reversing it because of the sophistication of those who want to spread malware and viruses (oh yay).

    To get the preview to work, I have to open it, print it to a new pdf and name it something different. Saving it as a pdf didn't work. If I want the original file name, after printing as a pdf with a modified name, I have to delete the original, then rename the one I printed back to the original name! At the current time, this is the only way I found to get around the failure to preview, and I found it by pure desperation. Thanks, Windows for creating a massive clusterf*!

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  2. Christian Schäftlmaier 0 Reputation points
    2025-12-17T10:32:32.2+00:00

    The information above was good, but I couldn't execute the Powershell command that way. I entered the key manually using regedit, and that worked:

    Screenshot 2025-12-17 112538

    New documents downloaded from the Internet are displayed in the preview again.

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  3. Mikael Matevosyan 5 Reputation points
    2025-12-13T08:25:18.2+00:00

    Guys this is the solution. Run PowerShell as administrator, then copy and paste the first command. Press enter. After that, copy and paste the second command, press Enter, and voilà.

    1. PS C:\WINDOWS\system32> New-Item `

    -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Policies" `

    -Name "Attachments" `

    -Force

    2.PS C:\WINDOWS\system32> Set-ItemProperty `

    -Path "HKCU:\Software\Microsoft\Windows\CurrentVersion\Policies\Attachments" `

    -Name "SaveZoneInformation" `

    -Value 1 `

    -Type DWord

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  4. Avi 5 Reputation points
    2025-12-13T00:17:10.0566667+00:00

    found this in an earlier post, so far it works - downside, need to run it everyday or multiple times a down.

    I copied the Commands (below) into a Word Doc and paste into Powershell, and run it more than once a day or multiple times. My files are on a server so for convenience, I keep PowerShell minimized but you must copy\paste the command each time. There's a was to write a script to have windows run it but this is beyond my skillset.

    Open Windows PowerShell {run as Admin}

    Change directory – for example, if your documents are in the ‘Downloads’ folderUser's image

    Type one of the following commands after the prompt ‘ >’  for the new directory path

    For : PDF Docs

    > Get-ChildItem "$env:C:*Downloads*" -Filter *.pdf -Recurse | Unblock-File

    For: EXCEL Docs

    > Get-ChildItem "$env:C:*Downloads*" -Filter *.xlsx -Recurse | Unblock-File

    For: TEXT docs

    > Get-ChildItem "$env:C:*Downloads*" -Filter *.txt -Recurse | Unblock-File

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