preview doesn't work in file explorer

Question

Hello, My problem (in PC and in my lapton) is that preview doesn't work in file explorer. Instead of preview, I get the message that "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 contetns". It's weird, because most of files has been opened before, and I was getting preview, but now it seems that it doesn't work. Our IT says that's a dysfunction in windows. Please help.

Answer 1

Hello, I'm afraid that nothing works. Please note that our PC has windows 10, and I deal with the same problem in my laptop even it has windows11 , updated. We've filled some websites in secure step, in order to stop blocking them, but downloads still are blocked.

Answer 2

Hi Christina,

This behavior is linked to recent changes introduced in the Windows 11 October 2025 update (KB5066835), which affects the File Explorer preview pane. Microsoft has tightened security protocols, causing certain files—especially PDFs and Office documents—to trigger this warning message.

To work around this, maybe you can try the following:

Add your network location to the Local Intranet zone via Internet Options to reduce false security prompts.

Ensure your preview handlers are enabled in File Explorer settings.

Check for updates from Microsoft, as a fix may be released in an upcoming patch.

If this helps resolve or clarify the issue, feel free to hit “Accept Answer” so others can benefit too 😊. Let me know if you’d like help walking through the steps!