I am running Office 2000 Professional and use Outlook as my mail program.  When I send a message with an attachment not all of the recipients receive the attachment.  I have discovered that those not receiving the attachments are using newer versions of Outlook Express.
What is the solution ?
Please Help
Derek Beauchamp (
Who is Participating?
wiskConnect With a Mentor Commented:
I see this has not been resolved yet. Are you by chance sending email in Rich Text Format? Are the users receiving Winmail.dat extensions instead of the actual attachment?

Pete LongTechnical ConsultantCommented:
Hi Octoloni,
Outlook Is Blocking Attachments

Go to the menu Tools > Options and click on the Security tab then uncheck the box
"Do not allow attachments to be saved or opened that could potentially be a virus"

If that Dosnt Work...

Quit Outlook 2000 if it is running.
Click Start, and then click Run.
In the Open box, type regedit, and then click OK.
Verify that the following key exists. If it does, go to step 5.

If the key path does not exist, create the key path. To create the key path, locate and then select the following registry key:

Click the Edit menu, click New, and then click Key.
Type Office, and then press the ENTER key.
Click the Edit menu, click New, and then click Key.
Type 9.0, and then press the ENTER key.
Click the Edit menu, click New, and then click Key.
Type Outlook, and then press the ENTER key.
Click the Edit menu, click New, and then click Key.
Type Security, and then press the ENTER key.
Click the Edit menu, click New, and then click String Value.
Type the following name for the new value:Level1Remove

Press the ENTER key.
Right-click the new string value name, and then click Modify.
Type the extension of the file type that you want to allow access to from Outlook 2000 as follows:.exe

To specify multiple file types, use the following format:

.exe; .com
When you are finished, click OK.
Exit Registry Editor.
Restart your computer.


Why does it block and what is level1 and level2?

Outlook 2000Sp3, Outlook2002, Outlook2003

This will do it for you in XP

Cannot Open E-Mail Attachments in Outlook Express After You Install SP1:;en-us;q329570 

OLEXP: Using Virus Protection Features in Outlook Express 6:;EN-US;291387

*****Blocked files are*****

The 38 file types automatically blocked by Outlook are as follows:

.ade      Microsoft Access project extension
.adp     Microsoft Access project
.bas      Microsoft Visual Basic class module
.bat      Batch file
.chm     Compiled HTML Help file
.cmd     Microsoft Windows NT Command Script
.com     Microsoft MS-DOS program
.cpl       Control Panel extension
.crt       Security certificate
.exe      Program
.hlp       Help file
.hta       HTML program
.inf        Setup  Information
.ins       Internet Naming Service
.isp       Internet Communication settings
.js         JScript file
.jse       Jscript Encoded Script file
.lnk       Shortcut
.mda     Microsoft Access add-in program
.mdb    Microsoft Access program
.mde     Microsoft Access MDE database
.mdz     Microsoft Access wizard program
.msc     Microsoft Common Console Document
.msi      Microsoft Windows Installer package
.msp     Windows Installer patch
.mst      Visual Test source files
.pcd     Photo CD image or Microsoft Visual Test compiled script
.pif       Shortcut to MS-DOS program
.reg      Registration entries
.scr       Screen saver
.sct       Windows Script Component
.shs      Shell Scrap Object
.url       Internet shortcut
.vb       VBScript file
.vbe      VBScript Encoded Script file
.vbs      VBScript file
.wsc     Windows Script Component
.wsf      Windows Script file
.wsh     Windows Script Host Settings file

rename the attachment extension
Upgrade your Question Security!

Your question, your audience. Choose who sees your identity—and your question—with question security.

Greetings, Octoloni!

To clarify, the problem is due to the receipients with newer versions of OE.  Go to the OE Options > Security tab and uncheck the box to block attachment.

Best wishes, war1
Remember why this blocking feature has been added as a default.
Viruses can be picked up nowadays without opening mail.
You could also send a host virus or worm to your recipient in all innocence, without being aware you have it.
The recent SOBIG.f virus is a classic example.
Simpler and safer solution...

Leave settings untouched.
Zip attachments before sending.
Inform recipients to do the same.
Virus check received zipped files before opening.

It's worth a few more keystrokes to...
OctoloniAuthor Commented:

Hi You are the closest so far and one recipient did say that that the message did receive a .dat extension with no attachment

How do I fix this ?
I could not find an active link, but, here is some text from an old link that I found about 1 year ago. The main issue is with Microsoft Outlook (not Outlook Express), you need to send emails in Text format instead of Rich Text or HTML. Or, upgrade to Outlook 2002, and that will resolve all of your problems.

Good Luck!

OL2000: (CW) Winmail.dat Attachments Included in Received Messages (Q197064)

The information in this article applies to:
* Microsoft Outlook 2000

NOTE: These procedures only apply if you have installed Outlook with the Corporate Workgroup/Other option. This option allows you to use Messaging Application Programming Interface (MAPI) services. To determine your installation type, on the Help Menu click About Microsoft Outlook. In About Microsoft Outlook you should see "Corporate" if you have the Corporate Workgroup installation. SYMPTOMS When you use Microsoft Outlook to send e-mail containing attachments through the Internet, some recipients using e-mail clients, other than Outlook, report that the mail message includes an additional file called Winmail.dat. The file is usually very small, but cannot be opened in the mail message.

The Winmail.dat file is used to preserve formatting that the sending client includes in the message, but is not recognized by the receiving client. In the case of Outlook, the Winmail.dat file includes Rich Text Formatting
(RTF) instructions. This type of formatting is used with the Microsoft Outlook Rich Text Format and when using Microsoft Word as an e-mail editor.

To avoid including Winmail.dat, use the Plain Text mail format. To select Plain Text for all messages, follow these steps: 1. On the Tools menu, click Options and then Mail Format. 2. In "Send in this message format", click to select Plain Text. To send to certain recipients with RTF format and others with Plain Text, you must set the option for the recipient in either the Personal Address Book or the recipient's contact record.

To set Plain Text by recipient in the Address Book, follow these steps: 1. On the Tools menu, click Address Book. 2. In Show Names From, select the Personal Address Book. 3. Select the addressee you want to set as Plain Text and on the File menu, click Properties. 4. Click to clear the "Always send to this recipient in Microsoft Exchange Rich Text Format" check box and click OK. To set Plain Text in the recipient's contact record, follow these steps: 1. Open the recipient's record in the Contacts folder. 2. Double-click the recipient's e-mail address. 3. Click to clear the "Always send to this recipient in Microsoft Exchange Rich Text Format" check box and click OK.
Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

All Courses

From novice to tech pro — start learning today.