PC Adm: How to Strand Attachment if It's too Large for System

Last reviewed: March 27, 1996
Article ID: Q124487
The information in this article applies to:
  • Microsoft Mail for Windows, versions 3.2 and 3.2a

SUMMARY

Sometimes a user will try to send a very large mail message (or a message with a large attachment) from Microsoft Mail for Windows. This can cause some network servers to run out of disk space or it can drastically slow network performance.

MORE INFORMATION

Only one copy of the message and attachment is kept on the postoffice (in the MAILDATA directory). When a message is sent to a user, a record goes into that user's mailbag (.MBG) file. The .MBG file in turn points to the message (.MAI) file on the postoffice. If there is an attachment, it is contained in an .ATT file, and the .MAI file contains a pointer that points to the .ATT file. Once the user reads his or her mail from the Windows client, all the messages and attachments get moved from the user's .MBG file into his or her personal Mail message file (.MMF).

RESOLUTION

If any users have not yet read mail containing the large attachment, a Mail administrator can prevent those users from reading the message by "stranding" the .ATT file on the postoffice. This procedure will remove the pointer to the .ATT file, so that Mail will not be able to download it to those users' .MMF files.

To prevent the mail message or attachment from interfering with any users who have not yet viewed the message from Microsoft Mail for Windows:

  1. Find a user who has not viewed this message in Microsoft Mail for Windows.

  2. Log in as that user from the MS-DOS workstation.

    Make a note of the message text that is listed under the subject of the mail message with the large attachment.

  3. Use the LISTUSER.EXE utility (available in Application Note WA0641) to get the hexadecimal ID (hexid) number of that user's .MBG file.

  4. Use DEBUG.EXE on the .MBG file and look for the message text from the subject line noted in step 2. From the C:\MAILDATA\MBG directory, type the following:

          debug 00000003.mbg
    

    This command will return a hyphen (-) sign. Type the following and then press ENTER.

          d
    

    Keep typing "d" until you see the message text. After the message text you will see an eight-digit hexadecimal number. This is the number of the .MAI file that points to the .ATT file. Type the following to exit DEBUG, and then press ENTER:

         q
    

  5. Go to the MAILDATA\MAI subdirectory. There are 16 subdirectories in the MAILDATA\MAI directory. The hexadecimal number you obtained in step 4 corresponds to a <hexid>.MAI file in one of the 16 subdirectories. For example, If the hexid number is 00000017, look in the MA7 subdirectory for 00000017.MAI. You can use Windows File Manager to search the MA* subdirectories for the location of the 00000017.MAI file.

  6. Rename the 00000017.MAI file to some other name, such as BADMSG.OLD.

  7. Have the user log in to the Windows client. From the View menu, choose New Messages. Double-click the message. The message will display the following error:

          ==== MAIL SYSTEM ERROR ====
          Mail could not read the entire message from the postoffice.
          Some parts of the message may be missing.  Ask the sender
          to resend the message.
    

    This error is expected. Anyone who has not yet read the offending message will receive this error, which means that the large attachment will no longer be circulating around the system.

NOTE: You can use the External Mail program MaxLanMailSize option to restrict the sizes of messages users can send to an external postoffice on the same LAN. For more information about how to use the MaxLanMailSize option, please see page 252 of the Microsoft Mail "Administrator's Guide."

LISTUSER.EXE is available to Mail administrators as part of Application Note WA0641, "Database Maintenance Utilities."

You can obtain this Application Note by contacting Microsoft Product Support Services.


Additional reference words: 3.00 3.20 attachment orphan large
KBCategory:kbenv
KBSubcategory: MailPCAdm


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Last reviewed: March 27, 1996
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