What Is a BAK File?
A file with the BAK file extension is a backup file.
Most BAK files are created automatically by a program that needs to store a backup.
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BAK files are sometimes created manually by a program’s user, too.
You might create one if you want to edit the file but not make changes to the original.
How to Open a BAK File
With BAK files, the context is especially important.

Where did you find the BAK file?
Was the BAK file named the same as another program?
Answering these questions could help find the program that opens the BAK file.
BAK files don’t work the same way as those types of files.
Doing this will enable Windows to properly use the key or value once again.
This naming practice is also sometimes done with folders.
Looking this up online tells you that it’s a metadata container used with MP3 files.
So, renaming the file tofile.mp3may be the solution to opening that particular BAK file.
Mostfree zip/unzip programscan open a wide range of file types, regardless of whether they’re an archive file.
Microsoft Outlook automatically generates BAK files when the Inbox Repair tool is used.
The backup file can be helpful, as it may contain items the Inbox Repair Tool couldn’t recover.