It is a file generated as an attachment by Microsoft Outlook or Microsoft Exchange Server. The name ATT00001 is a generic file name and is often seen in .htm, .dat, and other extensions when there is some sort of compatibility issue involving the sender and recipient’s Microsoft email program settings.
It is the result of an MIME file being sent and because of a compatibility issue; the redundant/additional txt file is generated and attached. Microsoft mail systems use Transport Neutral Encapsulation Format (TNEF) to pack and send this information, which is a proprietary format that sometimes leads to problems.
Main problems faced by user include:
Getting a message with an in-line attachment, followed by more text in which first attachment is displayed as another attachment.
The generated attachment file have names similar to 'ATT00001'
Why is Exchange Server Creating ATT00001 Attachments?
This happens if you tried to send a message that includes both text and attachment sections.
This can happen to any messages that pass through Exchange Server.
This is not dependent on the mail program; it can happen with any mail program.
It is often seen with Apple Mail because of the flexibility Mail gives in message format.
The only possible solution is to include attachments at the end of a message, after text and signatures. The Exchange Server insists that message text must always be first and attachments must always be last. As soon as the Exchange software sees one attachment in a message, it stops looking for text, and treats anything else in that message as attachment. Any remaining text sections are converted into attachment sections, and given fake file names (like "ATT00001.htm").
Below are some tricks, which can help the user to solve this issue:
Uninstall the Virus Scanner Connected With Outlook
The ATT00001 attachments issue occurs if MS Outlook is integrated with a virus scanner. Therefore, a user first installs the integration of the virus scanner with Outlook and then opens the emails.
Import Address Book Into Outlook
Users can import the contact list in Outlook and can assign manually which user’s emails won’t suffer from the ATT00001.txt file issue.
This can help in receiving the email without the hassle of extra-attached file, which the user can access using any version of Outlook mail client.
In Apple Mail
Any attachments added with the "Attach" paperclip button will put an end to the message after following below settings for all message text.
Go to the menu Edit > Attachments
Make sure the following settings are checked:
Always Send Windows-Friendly Attachments
Always Insert Attachments at End of Message
Use the menu Mail > Preferences and go to the Composing section
Make sure that Message Format is set to "Plain Text".
For Other Email Clients/Servers
It is recommended to use the text sections before attaching any file for preventing this issue at the receiver’s end.
There is no way that you can stop Exchange Server turning text sections into attachment sections. The ATT00001 attachments issue generally emerges when a user uses Outlook 2000/2003/2007 to receive the email. It rarely occurs if the email is accessed using webmail or using Outlook Express in POP settings.
ATT00001.txt file Email Attachment Issue is faced by many users. There is no perfect solution for it. But an email sender can be asked personally to fix his/her email before sending and requesting mailman administrators not to use footers.
Unfortunately, this will only fix one person who sends you mail, and wouldn't fix mail that a person get from other sources.
I hope the article help the users to understand the attachment issue of ATT00001 file while sending or receiving emails through Server.
For any query or suggestions, do comment.