Fix “Outlook blocked access to the following potentially unsafe attachments” error message in MAC Outlook

By | December 26, 2016

Fix "Outlook blocked access”

Frequently getting error message on your Mac outlook regarding the “Outlook blocked access to the following potentially unsafe attachments”? Well do you know why this error comes up to your screen and how can you fix this off? To know about this, you must read this tutorial….!

Folks who all send you mails disguised from person you might know but do you know about the malicious content they send as attachment. However Microsoft outlook will block registry files, executable files, JavaScript files and other files that are potentially hazardous. But sometime situation occur where you are totally sure about the attachment it does not contain any such harmful content but still you get an error message at the top of the message or of the Reading Pane, just like:

Error message will look like below (filename may differ):

Outlook blocked access to the following potentially unsafe attachments: attachment_filename.exe

Then how do you access the attachment when you are sure about the sender and the attachment is confirmed to be safe.

How then do you access the attachment when you are sure of the sender and the attachment is confirmed to be safe? This is another classic scenario of functionality versus security.

Almost every version of outlook service release security features that blocks attachments that might put your PC at big risk for viruses or other threats. Although outlook blocks access to the attachment, the attachments still exist in the email message.

Below here is the described method that you can use if you have to open an attachment that is blocked in outlook. Additionally , this article contains information about the types of attachment that outlook blocks.

How to tackles the Outlook blocked access attachments issue?

If outlook blocks an attachment, then it means you can’t open, save, print or work with that attachment. So to fix this problems easily follow the below mentioned steps.

General troubleshooting

outlook blocked access attachments

Method 1: Use a file share to access the attachment

Ask the sender to save the attachment to a server or an FTP site that you can access. Ask the sender to send you a link to the attachment on the server or FTP site. You can click the link to access the attachment and save it on your PC.

Method 2: Use a file compression utility to change the file name extension

If you don’t have such FTP site then you can ask the sender to use a file compression utility such as WinZip, to compress the file. This will generate a compressed archived file that has a different file name extension. Outlook don’t count these file name extension as potential threats. Therefore it doesn’t block the new attachment.

When the sender resends the new attachment to you just save it on your PC and after then with the help of any third-party file compression software extract the attachment from it.

Method 3: Ask the Exchange server administrator to change the security settings

If you use outlook with a Microsoft Exchange server and the administrator has configured the outlook security settings, the administrator might be able to help you out. Ask the administrator to do security settings on your mailbox to accept attachments such as the one which is blocked by the outlook.

If these methods didn’t work for you then try out the advanced troubleshooting.

Advanced troubleshooting

If you don’t use outlook with the exchange server or if the exchange server administrator allow users to change the outlook attachment security behavior, use Method 1:”Customize attachment security behavior.”

If you use outlook with an exchange server and the exchange server administrator has not allowed the changes to the outlook attachment security behavior the use Method 2: “Configure Outlook in an Exchange environment.”

Method 1: Customize attachment security behavior

In this section you will going to modify the registry settings. However any wrong step during this can make serious issue, so do it carefully. For protection, back up the registry before you modify it.

Follow these steps to modify the registry and change outlook’s attachment security behavior.

  1. If outlook is running on your PC then close it.
  2. Click Start, and then click Run. Copy and paste (or type) the following command in the Open box, and then press ENTER:


  1. Verify that the following registry key for your version of Outlook exists.
    Microsoft Office Outlook 2010


Microsoft Office Outlook 2007


Microsoft Office Outlook 2003


Microsoft Outlook 2002


Microsoft Outlook 2000


If the registry key exists, go to step 5.

If the registry key doesn’t exist, follow these steps to create it:

  1. Locate, and then click the following registry key.


  1. UnderEdit, click New, and then click Key.
  2. TypeOffice, and then press ENTER.
  3. UnderEdit, click New, and then click Key.
  4. For Outlook 2010, type0, and then press ENTER.
    For Outlook 2007, type 12.0, and then press ENTER.
    For Outlook 2003, type 11.0, and then press ENTER.
    For Outlook 2002, type 10.0, and then press ENTER.
    For Outlook 2000, type 9.0, and then press ENTER.
  5. UnderEdit, click New, and then click Key.
  6. TypeOutlook, and then press ENTER.
  7. UnderEdit, click New, and then click Key.
  8. TypeSecurity, and then press ENTER.
  1. UnderEdit, click New, and then click String Value.
  2. Copy and paste (or type) the following name for the new value:


  1. Press ENTER.
  2. Right-click the new string value name, and then clickModify.
  3. Type the file name extension of the file type that you want to open in Outlook. For example:


To specify multiple file types, use the following format:


  1. ClickOK.
  2. Exit Registry Editor.
  3. Restart your computer.

When you start outlook, you can open the file types that you specified in the registry.

Method 2: Configure Outlook in an Exchange environment

If you run outlook in an exchange environment, the exchange server administrator can modify the default attachment security behavior. For further information, regarding this, you must click the following link of Microsoft Knowledge Base:

290499 Administrator information about e-mail security features

263297 Administrator information about the Outlook E-mail Security update: June 7, 2000


If outlook blocks an attachment, then it means you can’t open, save, print or work with that attachment. So that it’s very important to troubleshoot this issues as quick as you can and for this above mentioned solution will surely going to help you a lot.