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Opening .exe Attachments and Outlook E-mail Security

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› Outlook › Opening .exe Attachments and Outlook E-mail Security

Last reviewed on February 13, 2018     11 Comments

Applies to: Outlook 2016 (Win), Outlook 2013, Outlook 2010, Outlook 2007

The Outlook E-Mail Security Update (included in Office 2000 Service Pack 2 and later versions) blocks access to .exe, .com and other "dangerous" files. See Attachment Security for a list of the affected file types. You cannot open these files from Outlook, nor can you use Outlook to save them to your system. If you try to forward a message containing an .exe file, Outlook does not include the attachment in the forwarded message.

blocked exe

With the rash of recent viruses using *.zip files to get past antivirus filters and bypass Outlook's attachment block, you may want to add the zip extension to the Level1Remove key to force users to save zips to their hard drive before opening or block access to zip files completely by adding zip to the Level1Add key.

So what do you do when you receive an .exe file and must find a way to open it? There are several methods, depending on your version of Outlook.

Recent Outlook Versions | Import to Outlook Express | Outlook Web Access | Tools | More Information

Recent Outlook Versions

Outlook allows the user (or administrator) to use a registry key to open up access to blocked attachments. (Always make a backup before editing the registry.) To use this key:

  1. Run Regedit, and go to the appropriate key for your version of Outlook (see list below)
    HKEY_CURRENT_USER\Software\Microsoft\Office\xx.0\Outlook\Security
  2. Under that key, add a new string value named Level1Remove.
  3. For the value for Level1Remove, enter a semicolon-delimited list of file extensions. For example, entering this: .mdb;.url would unblock Microsoft Access files and Internet shortcuts. Note that the use of a leading dot was not previously required, however, new security patches may require it. If you are using "mdb;url" format and extensions are blocked, add a dot to each extension. Note also that there is no space between extensions.

Outlook 2016:

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2013:

HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2010:

HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2007:

HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2003:

HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2002:

HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

Outlook 2000 SP3:

HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Outlook\Security
String: Level1Remove
Value format: .mdb;.url;

If you are using this registry entry, a glance at Help | About Microsoft Outlook will show Security Mode: User Controlled above the license information.

To force users to save *.zip files to the hard drive before opening, add .zip to the extensions step 3. See Block Additional File Types in Outlook for more information.

If you prefer not to edit the registry directly, you can use one of the tools below to make the change; not all support both Outlook 2002 and 2000.

After applying this registry fix or using one of the tools, the user still has to save the attached file to a system drive before opening it. In effect, the fix rolls the attachment behavior back to Outlook 2000 SR-1, with its included Attachment Security Fix. An end-user cannot bypass this "save to disk" behavior and open the file directly from the mail message, though an Exchange administrator can.

Import to Outlook Express

The newest versions of Outlook Express block attachments by default. To retrieve attachments, click Forward and save the attachment from the message, then close. It can also be disabled in OE's Tools | Options | Security dialog.

You can use either of the above methods to access .exe files from Outlook messages imported to OE. To make this process easier, consider creating a separate folder in Outlook to which you copy messages with attachments that you want to import. To import into OE, use OE's File | Import command.

Outlook Web Access

If you work in a Microsoft Exchange Server environment where Outlook Web Access is deployed, you may be able to use OWA to open messages and get the attachments. Exchange Server 2000's OWA has no attachment security, while Exchange 2003 added attachment security to OWA.

Blocked File Types

ExtensionFile TypeExtensionFile Type
.adeAccess Project Extension.mdzAccess Wizard Template
.adpAccess Project.mscMicrosoft Management Console Control File
.appExecutable Application.mshMicrosoft Shell
.aspActive Server Page.msh1Microsoft Shell
.basBASIC Source Code.msh2Microsoft Shell
.batBatch Processing.mshxmlMicrosoft Shell
.cerInternet Security Certificate.msh1xmlMicrosoft Shell
.chmCompiled HTML Help.msh2xmlMicrosoft Shell
.cmdCommand File.msiWindows Installer File
.cntMicrosoft Help Workshop.mspWindows Installer Update
.comCommand.mstWindows SDK Transform Script
.cplWindows Control Panel Extension.opsOffice Profile Settings File
.crtCertificate File.osdOpen Software Description
.cshcsh Script.pcdVisual Test
.derDER Encoded X509 Certificate File.pifWindows Program Information File
.exeExecutable File.plPerl script
.fxpFoxPro Compiled Source.plgDeveloper Studio Build Log
.gadgetWindows Vista gadget.prfWindows System File
.grpMicrosoft program group.prgProgram File
.hlpWindows Help File.ps1Windows PowerShell
.hpjAppWizard Help project.ps1xmlWindows PowerShell
.htaHypertext Application.ps2Windows PowerShell
.infInformation or Setup File.ps2xmlWindows PowerShell
.insIIS Internet Settings.psc1Windows PowerShell
.ispIIS Internet Settings.psc2Windows PowerShell
.itsInternet Document Set, Internet Translation.pstOutlook Personal Folder File
.jarJava Archive.regRegistry Data File
.jnlpJava Network Launch Protocol.scfWindows Explorer Command
.jsJavaScript Source Code.scrWindows Screen Saver
.jseJScript Encoded Script File.sctWindows Script Component, Foxpro Screen
.kshUNIX Shell Script.shbWindows Shortcut into a Document
.lnkWindows Shortcut File.shsShell Scrap Object File
.madAccess Module Shortcut.tmpTemporary File/Folder
.mafAccess.urlInternet Location
.magAccess Diagram Shortcut.vbVBScript File or Any Visual Basic Source
.mamAccess Macro Shortcut.vbeVBScript Encoded Script File
.maqAccess Query Shortcut.vbpVisual Basic project file
.marAccess Report Shortcut.vbsVBScript Script File
.masAccess Stored Procedures.vsmacrosVisual Studio .NET Macro Project
.matAccess Table Shortcut.vswVisio Workspace File
.mauMedia Attachment Unit.wsWindows Script File
.mavAccess View Shortcut.wscWindows Script Component
.mawAccess Data Access Page.wsfWindows Script File
.mcfMedia Container Format.wshWindows Script Host Settings File
.mdaAccess Add-in , MDA Access 2 Workgroup.xbapBrowser applications
.mdbMDB Access Database.xllExcel add-in
.mdeAccess MDE Database File.xnkExchange Public Folder Shortcut
.mdtAccess Add-in Data  
.mdwAccess Workgroup Information  
    

More Information

  • Outlook Email Security Update
  • Protecting Outlook against Viruses
  • How to configure Outlook to block additional attachment file name extensions
Opening .exe Attachments and Outlook E-mail Security was last modified: February 13th, 2018 by Diane Poremsky

Related Posts:

  • Block Additional File Types in Outlook
  • Embedded Objects are Blocked in Outlook Items
  • Disable the Unsafe Hyperlink Warning when Opening Attachments
  • Change Outlook's Programmatic Access Options

About Diane Poremsky

A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

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jorge (@guest_184219)
June 23, 2014 2:35 am
#184219

I tried your solution to unblock PDF attachments in a customer's computer but it didn't work still getting Attachment security warning and the attachment is removed. They still use windows xp and outlook 2003..

1
0
Reply
Diane Poremsky (@guest_184224)
Reply to  jorge
June 23, 2014 9:12 am
#184224

Version wouldn't affect it, as long as you used the correct key for that version. (You might need to restart Outlook for it to take affect.)

Try one of the addins - such as this one - https://www.codetwo.com/freeware/attach-unblocker/ - they set the same key but eliminate possible typos. If it still doesn't work, what antivirus/security software do you use?

0
0
Reply
Doug Bennett (@guest_184107)
June 17, 2014 3:56 pm
#184107

I tried your method of stopping outlook from blocking .com. Nothing even close. There must be many updates since your post. Thanks; God Bless you and yours.

0
0
Reply
Diane Poremsky (@guest_184119)
Reply to  Doug Bennett
June 17, 2014 10:24 pm
#184119

The Level1Remove method still works. You are talking about files ending in the .com extension? You need to add .com to the Level1Remove value. Links to .com websites are lnk or url extension.

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Reply
windows support (@guest_163005)
August 14, 2012 12:31 am
#163005

Love the site, thanks :)

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0
Reply
Bernard (@guest_151611)
July 18, 2012 4:13 pm
#151611

With Outlook 2003 (SP3) I get 'Outlook blocked access to the following potentially unsafe attachments...". This happens with .pdf files which I generated myself and attached to outgoing mail. Incoming .pdf attachments are not affected and open with a click, just not my own. I attach my invoices and receipts as PDFs and would like to review them before sending, but the security prevents this.
I tried the standard Registry "fix" offered by Microsoft, but that just seemd to have the opposite effect.
Any suggestions on how to turn this security warning off in outgoing mail?

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0
Reply
Diane Poremsky (@guest_151661)
Reply to  Bernard
July 18, 2012 6:42 pm
#151661

PDF's should not be blocked at all. Which registry fix did you try? Do not use Level1Add or Level1Remove keys. If you did, delete those keys.

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Dale (@guest_27186)
December 5, 2011 9:46 pm
#27186

I am unable to open any links in outlook it blocks everything says I have no access. What can I do to get this reversed. If I want to look at a job posting it will not let me access that job description

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0
Reply
Diane Poremsky (@guest_27192)
Reply to  Dale
December 5, 2011 10:16 pm
#27192

Is that the 'this operation has been cancelled due to restrictions in effect' error? If so, see Restrictions in Effect information - Edit Registry part 2 or Alan's solution work for most people.

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james latimore (@guest_25135)
December 1, 2011 3:01 am
#25135

This Help page doesn't help. I wanted to know how to prevent the "security concern" messages from popping up again and again---even after the items of concerrn have been disabled.? I have to cancel them each time I go into my email. How do youget rid of those things?

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Reply
Diane Poremsky (@guest_25141)
Reply to  james latimore
December 1, 2011 3:11 am
#25141

I'm not sure which dialog that is. Can you post the screenshot somewhere and post the url here or email me a screenshot? (diane at slipstick)

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0
Reply

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