Files with a .bak extension are used by a variety of applications on Windows and Mac but they have one thing in common. Their purpose is to be a backup file of an executable, registry, or utility file, a database, or even drawing or image and video editing projects. As such, the approach to getting them back in shape after recovery might be different. Fear not, because we’ve dedicated methods 3 and 4 to that problem. Granted, you’ll still have to do a little research because we can’t encompass every use. But, with that said, let’s get into how to recover .bak files.
1. Recover .bak files with built-in utilities
For Windows 10 users, we recommend starting with our “restoration of a deleted folder” guide. A backup copy encompasses all personal files while File History can target a specific folder where .bak backups are located. Skip the last headline, since we’ll cover this in the next method.
Is there a Mac alternative?
For Mac, you can use a Time Machine backup to recover .bak files:
- Make sure your Time Machine backup disk is connected.
- Open the Utilities window by pressing Shift + Command + U or searching “Utilities” in Spotlight.
- Launch Migration Assistant, and then select the From a Mac, Time Machine backup, or Startup Disk option.
- Select your Time Machine backup and click on Continue.
- Select which backup to restore, then which information to restore. To save time, limit it to the application whose backup you need. You can also select its entire installation folder.
- Click on Continue and wait for the process to finish.
- Try to open the application in question and load the backup. If this fails, move on to methods 3 and/or 4.
2. Recover .bak files using data recovery software
If method 1 produces no results, it’s time to pull out the big guns. Since these files are low in size, any of the data recovery software for Windows and Mac software for data recovery will do. If you need practical steps for .bak file recovery, look at the last headline (How to recover deleted files from a Pendrive) in our guide for recovering hidden files from a pendrive. If this works, move on to method 3.
3. Recovering .bak files via renaming
The trouble with .bak files, even when restored, is that the programs that use them sometimes refuse to load them. Usually, there’s a conflict with the latest backup. Oftentimes, the method of backing up was changed via updates. But, regardless of which .bak file it is, you can try to rename it to the original file name and type. So, follow these instructions to recover .bak files by renaming them:
1. Change filename to fit naming practice (Optional)
For some applications, how a backup file is named matters. To give you an example, backups of drawings in AutoCAD get this file name, filename_1_2_3456.sv$, when the application closes unexpectedly. The same goes for its .bak files generated by the automatic backup feature. Here’s what the filename represents:
- filename – name of the drawing.
- 1 – number of open instances of a drawing file in the same AutoCAD session
- 2 – Same as above, except in different work sessions
- 3456 – random numbers
- .sv$ – file extension of a backup file
2. Make sure file extensions are visible
Here’s how to unhide file extensions:
- For Windows. Follow steps 1 through 4 under the first headline in the pendrive guide mentioned in method 2. Remove a checkmark in front of Hide extensions for known file types.
- For Mac. Open Finder, then go to Finder > Preferences. Click on Advanced, then select Show all filename extensions.
3. Change the file name and type
On both Windows and Mac you can right-click on the file then select Rename. Now, which extension you choose matters, so do a little bit of research. To use the above-mentioned example, you can rename “filename_1_2_3456.bak” to “filename_1_2_3456.dwg” for AutoCAD drawings. After that’s done, simply try to open the file by double-clicking, or by opening the application and loading the file.
4. Convert or extract .bak files
Not all files can be restored by renaming, especially databases or registry files. So we’ll use a .bak file of an MS SQL database to show what can. Also, we’ll utilize software we have no affiliation with to demonstrate the process. So, this is how .bak file conversion/extraction process looks like:
- Download, install and open Stellar Toolkit for MS SQL (stellarinfo.com/sql-database-toolkit.php).
- Click on SQL Backup Recovery, then go to Browse, Scan, or Search, depending on if you know the location or need the software to find it.
- When it finds it, select the “database.bak” file and click on Scan.
- Now, in the Select Scan Mode window, click on Standard Scan or Advanced Scan, depending on the severity of the corruption of the backup file.
- Now you’ll see databases listed in the Select Backup Set window. Select individual ones or all of them.
- Click on Next and wait for the scan to finish. Select the format to save the databases extracted from the .bak file into – MSSQL (MDF), XLS, HTML, or CSV.