How to Unblock Unsafe Attachments in Microsoft Outlook

There’s a vast range of desktop and online email clients but it’s hard to beat Microsoft Outlook. The application has been around since 1997 and, despite a few dodgy decisions regarding HTML rendering, it’s still the email client of choice for me and many others.Unfortunately, there’s an Outlook message web developers hate:Outlook blocked access to the following potentially unsafe attachments…Thanks Microsoft. I know why you’re blocking that JavaScript file, but I know what it is and I really, really want it.Outlook doesn’t allow you to unblock unsafe attachments. Fortunately, there is a way to obtain the file and prevent the embarrassment of requesting a renamed version. Before we start…


We’re about to delve into the Windows registry. Please move along if you don’t know what the registry is or have never dabbled with it before. It’s a dangerous place — once false move and your PC will explode.

The fix will also reduce Outlook security settings. That’s not a problem for someone with reasonable IT knowledge, but it’s not for everyone.

Still here? OK, here’s what you do:

1. Close Outlook2. Run regedit.exe Navigate to:


Where XX.X indicates your version of Outlook:

14.0 for Microsoft Office 2010
12.0 for Microsoft Office 2007
11.0 for Microsoft Office 2003
10.0 for Microsoft Office 2002
9.0 for Microsoft Office 2000

3. Create a new valueCreate a new string value key in that location named:


4. Choose your ‘safe’ file typesEdit the key and enter a list of attachment extensions you want to unblock. Each should start with a period and be separated with a semi-colon. For example…To unblock JavaScript files only, enter:


To unblock JavaScript, VBScript, and exe files, enter:


Click OK to save the value then exit regedit.

5. Restart Outlook The attachment should be magically unblocked. Try rebooting if that’s not the case. Microsoft provide a useful support page with alternative options and configuration advice for those using Exchange Server.



Posted in Windows

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