Are you seeing the message “The file you are attempting to preview could harm your computer” while trying to preview PDF, Word, or Excel files in File Explorer on Windows 11 25H2 or Windows 10? You’re not alone! Many users reported that PDF preview stopped working after installing the latest Windows updates, including KB5066835 (Windows 11) and KB5066791 (Windows 10).
Full Error 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."
In this video, I’ll show you how to fix, solve, and repair PDF preview issues in File Explorer quickly and safely — whether you’re on a laptop, PC, or desktop running Windows 11 25H2.
Many users tried unblocking files, reinstalling PDF preview handlers, or uninstalling updates, but the issue often returned. This guide provides a permanent and working solution to restore PDF, Word, and Excel file previews in File Explorer.
🖥️ Applies to: All Windows 11 25H2 versions on Dell, HP, Lenovo, Asus, Acer, Microsoft Surface, MSI, Toshiba, Samsung, LG, and custom-built PCs. Also helpful for Windows 10 users facing similar preview issues.
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