Forum Discussion
Cannot Preview Network Files Within File Explorer
I am also facing this making my work much slower - everytime I have to open the document to see its contents.
Until recenty, every file preview was visible in the preview pane. Since the last few days, preview of some files are visible; for some, I get an error message - 'The file you are attmpting to preview could harm your computer. If you trust the file and the source you received it from, open it to view the contents'. But, previews of the ones with error message were visible a coupl eof weeks back and now they have become harmful!
Can someone please help solve this issue with Windows Explorer?
This is not a bug in the strict sense. Microsoft intentionally changed the behavior of the Preview to close a securety gap.
The cleanest and most sustainable fix is to add your network shares to the Local Intranet zone in the legacy Internet Options. Files coming from a zone Windows considers trusted will not get the Internet zone marking, and the Preview Pane will render them normally again. Uninstalling KB5066835 also resolves the issue, but is not recommended because it leaves the system without the October 2025 security patches.
Go to inetcpl.cpl. On the securety tab select Local Intranet -> Sites -> Advanced. Unchec "Require server verification (https:) for all sites in this zone" <- without this step the fix silently fails for SMB/UNC paths.
Then add your shares in the format file://servername, file://192.168.1.10, or file://*.company.local for a whole domain, clicking Add after each. Close all dialogs with OK.
If needed you can restart the File Explorer via Taskmanager so you dont have to reboot.
