How to Open a .bak File
.bak is not a format. It is a suffix that any program can add to a copy it is keeping, so what is inside depends entirely on what made it. The first step is identifying it, not opening it.
.bak
Why it will not open
- The extension describes intent, not content. A .bak might be a database, a config file, a document or a disk image — the name only says someone kept a copy.
- Whatever created it usually renamed the original. In many cases the file is byte-for-byte the earlier version of something, with .bak appended or substituted.
- There is no "bak opener", because there is nothing consistent to open.
How to open it
Identify it, then rename a copy
- 1 Drop it into the file identifier on this site — it reads the signature and names the real format regardless of the extension.
- 2 Copy the file, then rename the copy to the extension the identifier reported.
- 3 Open it normally. Work on a copy so that the backup stays intact if the guess is wrong.
Common cases
- 1 Alongside a document: usually the previous version of that document. name.docx.bak opens as a .docx.
- 2 From SQL Server: a database backup, restorable only through SQL Server Management Studio or the RESTORE command — not openable as a file.
- 3 From a game or an application: proprietary save data, useful only to that program, often restored by renaming it back over the current save.
- 4 From a text editor or IDE: plain text, safe to open in any editor.
Do not delete before checking
If the current file is damaged, the .bak may be the only intact copy. Identify it before clearing it out.