While many people want to unblock file types that are blocked by Outlook's security, with recent viruses using the zip file type to propagate, you may want to block zips to prevent someone from opening zips accidentally.
Choose between two options:
Level1Remove -- slow down access to the zip by forcing users to save them to the hard drive before opening them. With this enabled, users will be presented with a dialog like the one shown here when they double click on an attachment.
Level1Add -- treat *.zips like *.exes to completely block access to them.
Level1Remove
To Add file types to Level1Remove key:
- Press windows key + R to open the run command. Type Regedit and press enter to open the registry editor.
- Browse to the appropriate key for your version of Outlook
- Add a new String value named Level1Remove.
- For the value for Level1Remove, enter a semicolon-delimited list of file extensions. For example, entering this: .zip;.mdb;.url; would force you to save Zip file type and unblock Microsoft Access files and Internet shortcuts.
Outlook 2016 and newer
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security
String: Level1Remove
Value: .ext;.ext; format
Outlook 2013
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Security
String: Level1Remove
Value: .ext;.ext; format
Outlook 2010
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
String: Level1Remove
Value: .ext;.ext; format
Outlook 2007
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
String: Level1Remove
Value: .ext;.ext; format
Level1Add
To Block file types using the Level1Add key:
To add additional attachment file name extensions types that you want blocked, you must add the Level1Add key to the registry. To do this, follow these steps.
- Run Regedit browse to the appropriate registry key for your version of Outlook.
- Add a new string value named Level1Add.
- For the value for Level1Add, enter a semicolon-delimited list of file extensions. For example, entering .zip would treat the Zip file type like exe's and block access to them.
Outlook 2016 and newer
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Security
String: Level1Add
Value: .zip;.pdf; format
Outlook 2013
HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Security
String: Level1Add
Value: .zip;.pdf; format
Outlook 2010
HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Security
String: Level1Add
Value: .zip;.pdf; format
Outlook 2007
HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Outlook\Security
String: Level1Add
Value: .zip;.pdf; format
Tools
COM add-in by Outlook MVP Ken Slovak that adds an Attachment Security Options page to the Tools, Options dialog in Outlook 2000 SP3 or higher to allow you to manage which file attachments are blocked. New version adds support for the .gadget extension for Outlook 2003 SP3 and Outlook 2007 SP1. It also adds detection for those SP levels. Shareware. Version 1.9.6 | |
"Outlook blocked access to the following potentially unsafe attachment ..." If you get this message when attempting to access an Outlook email attachment you'll want to install Attachment Security for Outlook; a free program for unlocking attachments blocked by Outlook. Attachment Security for Microsoft Outlook is a free and easy to use software program that allows you to open attachments blocked by Microsoft Outlook e-mail security. | |
Developers can use this to avoid the security prompts in Outlook. |
just delete the Level 1 key and then restart outlook...worked for me.
The level1 key shouldn't exist by default, so yeah, if you (or an application) added it, delete it.
FYI, there is a THIRD level for extension types which will allow you to avoid saving the file first (at least for Outlook 2007) before opening it: OtherAdd
The meaning of the three levels are: Level1=Fully blocked, Level2=Prompt to Save, and Other=Prompt to open or save.
The way Outlook is supposed to work is that any extension not in Level1 and not in Level2 should fall to Other. That's not always true.
When creating a registry key for an extension, keep it simple and only use the level you wish to add your extension into.
In other words, don't use a Level1Remove and a Level2Remove hoping to get the desired extension added to the Other list; just use a single OtherAdd registry entry.
Lastly, when Outlook compares an attachment extension to the lists from the registry, IT IS CASE SENSITIVE! Therefore, say you want to allow Outlook to immediately Open the Excel 2003 .xls extension: Create a single key for OtherAdd and cover your bases by using the value of .xls;.xlS;.xLs;.xLS;.Xls;.XlS;.XLs;.XLS; (Also: REMEMBER TO END THE STRING WITH A SEMI-COLON!)
Hope that helps someone,
Sean
There is not actually an "other list" - it's just all of the extensions not blocked as unsafe. Unless things changed in a recent update, the extensions are NOT case sensitive - you should use lower case.
FWIW, Office files shouldn't be blocked. If the check box on the open or save dialog is turned off, open outlook using run as administrator and open the file - you'll be able to tick the checkbox to never ask again. More info: https://www.slipstick.com/problems/disable-always-ask-before-opening-dialog/
this page keeps re-loading in internet explorer. please fix
What version of IE are you using?