How to Open Octet-Stream File

When you attempt to download an unknown file from the Web or in an email attachment, your computer can recognize it as an Octet-Stream file. For your information, Octet-stream does not refer to a specific type of file. It can be anything from a spreadsheet to an executable program. By the way, how to open it?


To open an unidentified file, you have to figure out which program can open the file as a document or change the extension file to run as a program.

 Octet-Stream File

Files With Extensions

  • At the first step, you have to double-click the octet-stream file after downloading it. If the file contains a usable extension, it can load properly even if your email client or Web browser cannot identify it.¬†Alternatively, Windows is going to display a list of programs to try using.
  • The second step, you have to Step click a program in the list to load the file using the selected software. If you do not see any options in the list other than “Look for an app in the Store,” please click “More Options.” To choose a specific program not found on either list, simply click “Look for Another App on This PC.”
  • The next step that you have to do is to check whether the file loads properly. If it does not, you have to quit the program and try again with another application.
  • In this step, you need to double-click the file again, when you find a working application. Afterwards, you are able to navigate the box to ‘Use this app’ for all similar files and take the correct program. This associates the extension with the choice application for future use.

Files Without Extensions

  • At the first step, you have to double-click the file to display a list of programs on your computer. Please pick one to try loading the file. If the file does not load properly, you are able to quit the program and try another.
  • The second step, you have to choose the file after figuring out its type. Please press “F2” to rename the file and type its extension after the file name. For instance, if you find a file to be a Word 2013 document, you have to add “.docx” without quotes, and then press “Enter.” The typed extension is going to disappear but the icon of the file will change, recognizing its new type.
  • In this step, you are able to append the extension “.exe” if you need to run a file as an application, rather than as a document in another program. Files which appear as octet-stream files are frequently applications, but you have to only run a downloaded application if you trust its source.

Well, this is the way to open an Octet-Stream file. We are sure that now you are able to follow those steps above if you want to open an Octet-Stream file.


The Octet-Stream file is used for file attachments on the Web with an unknown file type. Those Octet-Stream files are arbitrary binary data files which may be in any multimedia format. The Octet-Stream was expanded for Web browsers to understand which the file attachment is in an unknown file type. Also, it offers the user to select to download and save the attached file in any file format that the user wishes. In other cases, the Octet-Stream file format is used to announce to the user that the attached file can be saved in a recommended file format.

Simply, those Octet-Stream files can be opened by renaming the extension of the attached file to a specific file extension, and then by utilizing an application with support for opening such files. For instance, an Octet-Stream file can be renamed to a .txt file and then Notepad may be used to open the file. It means that you need to know the file type of the attached Octet-Stream file before renaming the file in the right file extension.


You have to know that an Octet Stream is the binary version of a MIME-type file. For your information, MIME-type files are those sent and received through Servers, Browsers, and Web Clients. An octet is an eight-bit byte. An octet-stream file can be any file format such as a .jpeg or an .exe renamed during transmission from source to destination. Also, the Octet streams are known as byte streams.

Apparently, Browsers and email clients rename files with missing extensions to octet streams routinely. If you have trouble opening an octet-stream file, one must try to rename the file extension if the file type is known or displayed once you are downloading an attachment. If the file type is unknown and cannot be determined easily, you have to ask the sender regarding the file type before trying to rename the file. If an extension is renamed correctly, now the file should open easily. Another option is to open the appropriate program for the file type and try to open the file in the program without renaming the extension. Please be sure to open the file in the appropriate application based on the file type. Usually, the Octet-Stream files are executable application files. If you still have trouble when you are opening a file, please request that the sender try to retransmit the file. Based on our experience, The Web Clients and Email are seldom able to open Octet Stream files, however may be able to specify the appropriate program to open the file.

Well, this is an explanation about how to open Octet-Stream File and some information related to Octet-Stream File. Now, can you understand how to open an Octet-Stream File? We hope you are able to understand it. But, if you are still confused, we allow you to send us an email for assistance.