The file extension _DOC is associated with Microsoft Word and Windows Live Mail. Microsoft Word is a word processing application which is part of the Microsoft Office suite of productivity applications. Windows Live Mail is an email client created by Microsoft which allows you to send and receive emails, read news feeds, and access other information over the Internet.
Microsoft Word is commonly the origin of the file extension DOC. File extension _DOC is categorized as a document file type which contains text, formatting, images, templates, letterheads, and other elements which are used to create professional documents. The main difference between the file extension _DOC and DOC is the _DOC extension is created as the result of a bug in the Windows Live Mail application when the sender attaches the document to an email message. This is known to happen in Windows Live Mail when a file name contains multiple symbols, including periods in the base name, before the extension.
When you use the Send to Mail Recipient feature the DOC file is inadvertently altered when attached to the email message. On the other hand, when you drag and drop the DOC file into the email message, the file extension appears with a period before the DOC file extension as opposed to an underscore.
The problem with the underscore placed before the DOC extension is the file cannot be opened when the recipient double clicks on it. Instead, the recipient receives a message that states Windows could not open the file since there is no program associated with it.
How to Open _DOC Files
If the DOC file extension has been changed to display an underscore, you can open the file by changing the _DOC file back to an extension which contains a period. You can accomplish this by right clicking on the _DOC file and then choosing Open With from the drop-down menu. When the list of applications appears, click on Microsoft Word and then select Always use the selected program to open this kind of file. If Microsoft Word is not in the list, you can click on Browse to locate the program in your PC.
If opening the _DOC file is still unsuccessful, you can try renaming the file to reflect the DOC file extension with a period instead of an underscore. You can do this by saving the _DOC file to My Documents or other location. Once the file is saved, locate the _DOC file and right click on the file. Choose Rename from the drop-down menu, and when the prompt box appears, change the _DOC file extension to .DOC with a period.
Once the _DOC file extension is changed to a period, there is an unlimited amount of ways you can open the file using various different programs and applications, including Microsoft Word or OpenOffice Write, which is an open source word processing application available as a free download on the OpenOffice.org website.
Once the file extension _DOC is changed to the .DOC extension, you can also open the file using any text editing application such as Notepad or WordPad for Windows, Apple TextEdit for Mac, or gEdit and Nano Editor for the Linux operating system.