According to the information from the KB5066791 update released on October 14, 2025, Microsoft has strengthened security measures for Windows 10, especially regarding the handling of files downloaded from the Internet.
🔐 Related content in KB5066791:
File Explorer automatically activates protection mode for files downloaded from the Internet or unknown sources.
When you try to preview or open these files, the system will display a warning as shown in the image you sent: “The file you are trying to preview may harm your computer…”
The goal is to prevent malicious code or dangerous software from being activated through the preview operation.
How to fix if you want to disable this feature:
You can unblock the file in the following way:
Right-click on the file → select Properties
In the General tab, if you see the line “This file came from another computer and might be blocked”, click Unblock.
Click OK to save the changes.
Unblock Multiple Files Using PowerShell
📌 1. Open PowerShell with administrative privileges
Press Windows + X → select Windows PowerShell (Admin)
📄 2. Run the following command to unblock all files in a folder:
powershell
Get-ChildItem "C:\Path\To\Folder" -Recurse | Unblock-File
🔍 Explanation:
Get-ChildItem: get a list of all files in the folder
"C:\Path\To\Folder": replace with the actual path to the folder containing the file you want to unblock
-Recurse: applies to subfolders
Unblock-File: command to unblock files
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