How to Stop Windows 10 From Blocking Your Downloaded Files

When you try to open a file, Windows 10 might prevent you from opening it directly. It’ll show you a security warning that the file originated from an unknown source and can be insecure. This happens when a Windows 10 feature called the Attachment Manager blocks files that it considers unsafe for your PC.

While you could manually unblock each file, this can be a tiring process—especially if you have to do it for almost every file you download. In this article, we’ll show you how you can stop Windows 10 from blocking your downloaded files.

What Is the Attachment Manager in Windows 10?

In Windows 10, there’s a security feature called the Attachment Manager that blocks you from opening unsafe files. These can be files you’ve downloaded or files that Windows identifies as unsafe email attachments. If the Attachment Manager considers a file unsafe, it prevents Windows 10 from opening it and displays a warning message. The Attachment Manager classifies files that you download based on the file type and the file name extension.

Windows Attachment Manager uses the IAttachmentExecute application programming interface (API) to find the file type, the file association, and to determine the most appropriate action to take. When you download files and save them on your disk, Windows adds specific metadata to these files. These metadata are considered to be attachments. When Windows adds metadata to the download files as an attachment, this is known as Zone Information.

Now, the Zone Information is where the root of the matter lies. When File Explorer opens a file, it reads the attached Zone information stored in the same location and checks to see if the file came from an unknown source or not. If Windows finds that the file is unrecognized or came from unknown sources, it prevents you from opening it.

A Windows SmartScreen warning will appear stating:

Windows SmartScreen prevented an unrecognized app from starting. Running this app might put your PC at risk.

If you wish to manually open a blocked file, right-click on the downloaded file and then select Properties. In the General tab, click Unblock, click Apply and then click OK.

But, imagine you have to do this every time you download a file—that can be annoying and time-consuming. If you often download files from the internet or receive files as email attachments, you might want to completely stop your PC from blocking your files.

To stop Windows 10 from blocking you from opening your files, you need to prevent it from adding Zone Information to the files you download. You can do this by configuring the Attachment Manager manually using the Local Group Policy Editor or the Registry Editor.

We’ll provide steps on how you can do this. You must be signed in as an administrator or you should request administrator rights to be able to stop downloaded files from being blocked.

Configure the Attachment Manager Using the Registry Editor

Press the Windows Key + R to open the Registry Editor. From there, type “Regedit” and click Enter. A User Account Control prompt will pop up. When this prompt appears, click the Yes button to continue.

Navigate to the Attachments key in the Registry Editor: HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > Policies > Attachments.

If the Attachments key is absent within the Policies key, you’ll have to create it. To do this, right-click on the Policies key, click New, click Key. This will create a new key, which you should then name “Attachments”. If you find that the Attachments key is already present, you can skip to the next step.

Right-click on the Attachments key, click New and then select DWORD (32-bit) Value.

You’ll be requested to name this newly-created DWORD value. Name it “SaveZoneInformation” and click Enter.

Finally, to disable the Attachment Manager in Windows 10, double-click on the newly-created SaveZoneInformation value and change its value data to 1. Click OK to finish.

When you complete these steps, close the Registry Editor and restart your computer to apply the changes. From here onward, any file you download will no longer attach Zone Information to the file’s alternate data stream. This will allow you to open your files without any difficulties.

If you’d like to go back and enable the Attachment Manager, you can do this by navigating to the Attachments key in the Registry Editor: HKEY_CURRENT_USER > Software > Microsoft > Windows > CurrentVersion > Policies > Attachments. From here, on the right-side, double-click on the SaveZoneInformation value and change its value data to 3.

Configure the Attachment Manager Using the Local Group Policy Editor

The Local Group Policy Editor is only available in the Windows 10 Enterprise, Education, and Pro editions. As a result, this method isn’t applicable if you own the Windows 10 Home edition. If your PC runs on the Windows 10 Home edition, you’ll need to configure the Attachment Manager via the Registry Editor.

If you’re using a Windows 10 edition that has the Local Group Policy Editor, you can configure the Attachment Manager using the steps indicated here.

To get started, press Windows Key + R, type “gpedit.msc”, and click Enter to open the Local Group Policy Editor.

Navigate to the Attachment Manager: User Configuration > Administrative Templates > Windows Components > Attachment Manager.

In the right pane of the Attachment Manager, double-click on the Do not preserve zone information in file attachments policy to edit the Zone Information settings.

A window will pop up where you can choose whether the Attachment Manager should or shouldn’t preserve Zone Information.

Click Enabled to allow the Attachment Manager to not preserve Zone Information. This will ensure that Windows doesn’t block your files whenever you open them. Click the Apply button to save the changes and then click OK.

When you finish, close the Local Group Policy Editor and reboot your PC to save the changes.

Windows Won’t Block Your Files Anymore

If you’ve previously had to manually unblock most of the files you downloaded, you’d have realized how tiring that process could be. Once you apply these tips, you’ll have the freedom to open all your files with ease.

If you download files and somehow doubt their credibility, you can always open them in secure isolated environments to ensure that your PC and data are safe.

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