.bad File Extension

.BAD File Extension/File Type

The file that ends with .bad file extension is a simple text file that contains actual SMTP format message which is not delivered/sent or failed to send by Microsoft Exchange Server. All the .bad file type stored under the Badmail folder on the server.

Each bad file contains individual, not delivered email with the sender, recipient, subject and even body. And the file is executed in the Outbox folder and marked as not sent or not delivered by the Microsoft Exchange Server. We can see the output of a BAD file in the MS Outlook draft folder/outbox folder. The entire mail server was developed by Microsoft and used in Outlook product.

Name Description
File Type Microsoft Exchange Server File
Developer Microsoft inc.
Category Text file
Status Active and used in Microsoft Exchange Server

Technical Information

Each BAD file is created and generated using a variable syntax operated by the server. The following example describes the method of generating the .bad file extension based file in the Badmail folder of individual user’s database.

  • TEST.bad
    To: <var>Username</var>@<var>Mail_Domain</var>
    From: <var>Native_Username</var>@<var>Native_Domain</var>
    Subject:  <var>Mail Subject</var>
    This is a test mail
  • Another file type you may encounter in the Badmail folder. One or more .bdp file can be found in the Badmail folder. It is actually connected with .bad file and points to local .eml file. A .bdp file indicates diagnostic messages to the users. The absolute server path of a local .eml file can be:
  • You can also see a file that ends with the .bdr file extension. This file also connected with a .bad file that contains message sending error code and message sender and recipient information. See the example below:
    Unable to send this message because the following errors were encountered:
    Unable to deliver the message, the error code was 0xC00402C7.
    The message sender was: <var>Sender_Username</var>@<var>Sender_Mail_Domain</var>
    The message was recieved by the following recipients:

Programs that open BAD file

BAD file is not a commonly used file type. It was designed and developed by Microsoft and used in the Microsoft Exchange Server to store the undelivered message only. So this file is only executed by the Microsoft Mail Server (Microsoft Exchange Server). However, you can view or edit this file using advanced text editors (e.g: Notepad++).

Operating System Programs
  • Microsoft Exchange Server (Mail Server)
  • Notepad++
  • Any other Advanced text editor