How to Disable the ‘These Files Might Be Harmful to Your Computer’ Warning

Robert Hayes October 23, 2019

One of the most powerful but sometimes frustrating features of Windows as an operating system is the powerful, if inconsistent, support for putting your home and office PCs on networks sharing resources between them. One common task in such a setup is to map a network drive to your own Windows PC using its IP address. If you’ve mapped a network drive or server to your Windows PC via its IP address, you may see a warning message when attempting to transfer files from the network location to your local drives: These files might be harmful to your computer. Clicking “OK” dismisses the warning and transfers your files, so it’s not a major issue for occasional file transfers. But if you frequently transfer files between your local and networked PCs, having to dismiss this warning every time can quickly become annoying.

How to Disable the 'These Files Might Be Harmful to Your Computer' Warning

(In case you’re wondering: no, Windows doesn’t think that there’s anything particularly suspicious about your files. It’s just recognizing that the files are coming from somewhere else, and so it’s issuing a warning – like having a watchdog who never learns to recognize family members and goes berserk no matter who comes to the door.)

Although this persistent warning message can be very annoying, it is possible to turn the warning off so that it won’t constantly interrupt your work. This is accomplished by modifying the way tha your Windows PC views your network storage devices. In this article, I will show you how to disable the These files might be harmful to your computer warning message in Windows. The screenshots and workflows presented here are for Windows 10, but the process is largely identical for Windows 7 and Windows 8. (Windows 7 networking can be a little different than in the most recent versions; you may want to check out our guide to setting up network sharing in Windows 7.)

Windows 10 – These Files Might Be Harmful to Your Computer

The option we want to change is located in the Internet Options control panel. The quickest way to get there is to simply search for Internet Options from the Start Menu. Alternatively, you can navigate to Control Panel > Network and Internet > Internet Options.

From the Internet Properties window that appears, select the Security tab at the top of the window and then click the Local Intranet icon. With Local Intranet selected, click the Sites button.

A new window labeled Local Intranet will appear. Click the Advanced button at the bottom of the window.

Here, you can add the IP addresses or DNS names of your locally networked PCs and storage devices. Windows will treat any addresses added here as trusted local resources and will therefore not bother to warn you when you transfer files from them. For example, we have a NAS that has been mapped to our local PC via its IP address (192.168.1.54).

Entering that address in the top entry box and then clicking Add will instruct Windows to trust connections to this device. If you have many networked PCs and devices, you can use wildcards (*) to avoid having to enter all of their individual addresses manually. Continuing the example, if we wanted Windows to trust all of the locally networked devices on our subnet, we could enter 192.168.1.* which would cover everything.

Just make sure you know and trust the devices on your network. If you’re in a shared environment, adding all devices to your trusted list could result in potential security vulnerabilities, as you won’t receive any warnings when transferring files from unsafe or compromised devices.

Once you’ve added your desired addresses, just click Close to save your change and then OK on the Local intranet window. You can then close the Internet Properties window. If you’re already connected to one of the servers you just added, you’ll need to disconnect and reconnect to it for the change to take effect. You’ll now be able to transfer files from any of the PCs and devices you designated without seeing the These files might be harmful to your computer warning.

Your internet security settings suggest that one or more files may be harmful

Some users may occasionally see the error message Your internet security settings suggest that one or more files may be harmful. This is related to the issue above, but uses a different aspect of the way Windows shares network files. If you are using DFS (Distributed File System) then you may see this error message when moving files within the network drive. The solution to this problem is to add the DFS root path to the Internet Explorer Local Intranet Zone. This can be done either locally on each individual machine, or via Group Policy.

To solve it locally, machine by machine:

Open Internet Explorer > Internet Options > Security tab
Select Local Intranet and click on Sites.
Click on Advanced and add your DFS Root in format: file://domain.local

To solve it on all machines in your workgroup by setting a Group Policy:

User Configuration > Policies > Administrative Templates > Windows Components > Internet Explorer > Internet Control Panel > Security Page.
Enable Policy called Site to Zone Assignment List.
Click Show and your DFS Root in format file://domain.local (value for Local Intranet should be 1).

Do you find yourself doing a lot of Windows file management, especially via the network? You probably could use some help with that – and help is here, with this excellent guide to Windows file management.