Learn Methods to Open Blocked Attachments in MS Outlook

About Outlook, November 18, 2017

It is a basic and known fact that about 60% of the viruses are spread through attachments. Some hackers or competitors can sent you a message containing viruses and all your vital information will be seized. There is no particular method or file extension that helps you to determine whether a file is safe or contains viruses.

Outlook cannot scan for Viruses and therefore it is not possible to decide whether a mail is safe or not. However, there are some specific files, like the Executable and Scripted files, that are considered as a platform to spread viruses. For the security of its users Outlook simply blocks these files. The advantage of blocking files is that even unidentified viruses are blocked. On the other hand, you will be restricted from accessing a healthy file.

On receiving an email, containing blocked attachments in MS Outlook the following message will be displayed to you:

Outlook blocked access to the following potentially unsafe attachments.”

Methods to Open Blocked Attachments

One of the following methods can be selected to open an attachment that is blocked in Microsoft Outlook:

METHOD1: Changing Exchange Server Security Setting

In MS Exchange Server, certain restrictions are applied by the Administrator that prevents the users to receive mails of a particular type. However, if you know that the file you are receiving is secure enough, you can ask the Administrator to change security so that you can receive the desired attachments.

METHOD2: Customizing The Security Behavior Of Attachments

You can modify the registry and change security behavior of Outlook for attachments so that the blocked attachments in MS Outlook can be viewed. The following steps are required to be followed for the process:

  1. Close Outlook, if it is running.
  2. Move to Registry Editor.
  • For Windows 2000 – Type regedt32, in Run command.
  • For Windows Vista and 7 – Type regedit in the search box of the start menu.
  • For Windows 8 and above – Type regedit in the search box of the start screen.
  1. Navigate to following key according to the version of Outlook configured in your local machine.version of OutlookSecurity
  2. In the Registry Editor, navigate to the following location:

Edit/New/String Value.Registry Editor

  1. Provide a name to the value as Level1Remove.

Note: The name of the value is case sensitive.Level1Remove

  1. A newly created value will be visible in the Registry Editor.
  2. Double click on the value and enter the extension of the file that you want to open.


  • Enter the extension with a dot.
  • If you want to add more than one extension, separate them with semi colon.
  1. Click on OK to close the Registry editor.
  2. Restart your Local machine.

METHOD3: Using a Compression Tool

The sender can be asked to use a Compression tool in order to compress the original file. These tools create files with different extensions which are not considered as threat by Outlook and hence, it does not block the attachments. On receiving the files, which were initially blocked attachments in MS Outlook, you can save it on your local machine and then extract attachments by either using a third party tool or by simply following these steps:

  • Navigate to email attachment and copy it.
  • Paste the attachment on the desktop.
  • Rename the attachment using the original file extension.

Now, you will be able to view the attachments on your local machine that was blocked by Outlook. However, you need to be technically sound to perform these steps as any mistake can lead you to loss of information.

Wrapping Up

We understand the concern of users that attachments play an important role. Therefore, we have come up with a solution to open blocked attachments in MS Outlook to maintain the workflow.

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