Microsoft told Windows Latest that it disabled the File Explorer Preview pane in Windows 11 25H2 and 24H2 for internet downloaded files. If you create a file locally, you can still preview it, but File Explorer Preview won’t work for files downloaded from the internet due to security reasons.
For those unaware, File Explorer has two panes by default. When you click on ‘View,’ it lets you toggle between Details and Preview. While the Details pane gives a brief breakdown of file information, such as the author of the file, creation time & date, the Preview Pane lets you quickly preview the file’s content without opening it.
You just need to select the document, and its preview will automatically appear on the right side of File Explorer. Other file formats, such as .docx and even .py (Python), are also supported.
However, File Explorer now shows the following error when you try to preview files downloaded from the internet or a remote network:
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.
Windows Latest observed the behaviour for all files downloaded from the internet.
Tested: Why does the File Explorer Preview Pane no longer work for some files?
After I installed the updates and casually opened the downloads folder, I noticed that most of the .PDFs were not showing a preview on the right side of the File Explorer. Instead, it shows an error message warning about potential security risks associated with the file, so it won’t be previewed.
Now, Microsoft says it’s an intentional change.
Why Microsoft disabled File Explorer Preview in Windows 11?
Microsoft turned off the permission for Internet downloaded files to patch an edge case where attackers could grab your sign-in proof by exploiting NTLM. For example, if you accidentally download a malicious file, and it contains links, File Explorer would try to preview it, and it’ll also follow links inside the file as part of the process.
The catch is that the automatic fetch can send your NTLM hash in the background, which an attacker can capture and abuse. You didn’t even open the file yet, but just selecting it was enough to trigger the risk.
So Microsoft flipped a policy switch that tells Explorer, “don’t preview internet-zone files,” and we have the above error as a result.
“Starting with Windows security updates released on and after October 14, 2025, File Explorer automatically disables the preview feature for files downloaded from the internet,” Microsoft told Windows Latest in a statement. “If you are confident in the safety of both the file and its source, you may remove the internet security block.”
If you trust the file, you just need to right-click, select Properties, and check ‘Unblock’ under the security section.
While it’s a simple workaround, it still defeats the whole purpose of ‘quickly‘ previewing files in Explorer. If you need to click four times to see a preview, you might as well open the file, which would not take more than two clicks. However, thankfully, there’s a PowerShell script that lets you unblock all files in a specific path.
In PowerShell, you just need to run the following command:
Unblock-File -Path "C:\Users\admin\downloads\*.pdf"
It will unblock all .pdf files in the downloads folder, including those you plan to download in the future. As long as you trust what you download, this should be good to go. You can run the same script for other paths or file types.
This change is rolling out as part of Windows October 2025 Patch Tuesday, which is the same update that broke WinRE (Windows Recovery Environment) and even LocalHost.
