See Your Documents in Windows Preview.
SimpleUNLOCK is a free Windows desktop program that helps restore document previews in File Explorer when downloaded-file security marks are blocking them. Review documents in the Preview pane without opening each file or manually unblocking it.
Why Windows Blocks Some Previews
Starting with security updates released on October 14, 2025, affected Windows installations block previews of internet-marked files. Instead of the document, you may see:
“The file you are attempting to preview could harm your computer.”
This is a precaution based on where the file came from, not necessarily a detected virus. Read Microsoft’s explanation.
Scan Before Unblocking
Choose folders you trust. SimpleUNLOCK checks each eligible document and requires a completed clean scan through a supported antivirus scanner before removing its internet-origin security mark. It verifies that the document contents remain unchanged. Detections, scan failures, and unsupported scanners leave documents blocked.
Monitor Your Folders
Include subfolders when needed, pause individual folders or all monitoring, and optionally start with Windows. SimpleUNLOCK runs from the notification tray and processes existing and newly arriving marked documents in enabled folders.
Supports PDF, DOCX, XLSX, PPTX, TXT, and CSV. Programs, scripts, legacy Office files, and macro-enabled documents are excluded. Activity shows scan results, files that remain blocked, and successful unlock totals.
Use Trusted Sources
A clean scan does not guarantee a document is harmless. Removing its security mark can also affect other application warnings and protections. Previews still require compatible preview software; network-share restrictions and unrelated preview problems may remain. SimpleUNLOCK does not change Windows-wide marking policies or share security zones.
Completely Free
Provided by Precast Simplified at no charge, with no subscription, license key, or activation required.
