.bak

File Type 1 Backup File IconBackup File
File Format Standard
Usage Referenced by an application; not meant to be opened manually; may run a program or script when opened
Rank ★ ★ ★  Common
Description

Backup of another document, often created automatically by the operating system or various programs such as Autodesk AutoCAD; Windows may create BAK files for the System.ini and Win.ini files.

Important: The file extension should be changed back to the original extension in order for the file to open correctly. This is often done by simply removing the ".bak" part of the filename. For example, "mydocument1.doc.bak" should be renamed to "mydocument1.doc" before being opened.

Open With
Windows

IconAutodesk AutoCAD

IconMicrosoft SQL Server

IconOriginal program used to create the file

macOS

IconOriginal program used to create the file

Updated April 21, 2009
File Type 2 Generic IconFirefox Bookmarks Backup
File Format Proprietary (Mozilla)
Usage Open manually; may be referenced by an application
Rank ★ ★ ☆  Average
Description

Backup of the Firefox bookmarks file; can be used to replace saved bookmarks in case the main bookmarks file becomes corrupted; automatically generated by the Firefox Web browser; typically named "bookmarks.bak"

The bookmarks.bak file is located in the following directories on Windows and Macintosh systems:

Windows
C:\Documents and Settings\UserName\Application Data\Mozilla\Firefox\Profiles\[randon-name]
Mac
/Users/[username]/Library/Application Support/Firefox/Profiles/[random-name].default

Open With
Windows

IconMozilla Firefox

macOS

IconMozilla Firefox

Updated 2007
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