What Is a BSA File?

How to Open, Edit, & Convert BSA Files

A file with the BSA file extension is a BSARC Compressed Archive file. The BSA stands for Bethesda Software Archive.

These compressed files are used to hold resource files for Bethesda Softworks computer games, like the sounds, maps, animations, textures, models, etc. Storing files in BSA archives makes organizing the data much easier than having them exist in dozens or hundreds of separate folders.

BSA files are stored in the \Data\ folder of the game's installation directory.

BSA files in Windows 10

How to Open a BSA File

The Elder Scrolls and Fallout are two video games that may associate with BSA files, but these applications automatically make use of the BSA files they find in the proper folders—you can't use these programs to open a BSA file manually.

To open a BSA file to view its contents, you can use the BSA Browser, BSA Commander, or BSAopt. All three of these programs are standalone tools, which means you just need to download them to your computer in order to use them (i.e., installation is unnecessary).

Those programs download within either a 7Z or RAR file. You can use a free file extractor program like 7-Zip to open them. On that note, a file decompression utility like 7-Zip should be able to open the BSA file as well since it's a compressed file type.

If the BSA file won't open in any of the above programs, you may have better luck with Fallout Mod Manager or FO3 Archive. These tools are designed to open BSA files from the Fallout video game, and may even allow you to edit them, providing a clever way to customize gameplay.

If when you open the BSA file, it launches with a program you don't want to use the file with, you can change which program should open BSA files by default.

How to Convert a BSA File

Converting a BSA file to another archive format (like ZIP, RAR, or 7Z) probably isn't something you want to do. If you were to convert it, the video game that uses the file would no longer recognize the archive, which means the contents of the BSA file (the models, sounds, etc.) wouldn't be usable by the game.

However, if there are files within a BSA file that you want to convert for use outside of the video game (e.g., audio files), you can use a file unzip tool to extract/unpack the data, and then use a free file converter to convert the files to other formats.

For example, maybe there's a WAV file within the BSA file that you want in the MP3 format. Just extract the WAV file from the archive and then use a free audio file converter to convert WAV to MP3.

Still Can't Open the File?

If your file still isn't opening even after trying the programs above, re-read the file extension to make sure you aren't confusing it with a file format that shares similar file extension letters.

For example, a BSB (BioShock Saved Game) file is created by the BioShock game—you can't open that file with the programs mentioned above even though the file extension is similar to BSA.

BSS is another example. This file extension belongs to the background image format used with the Resident Evil PlayStation game. BSS files can be opened on a computer with Reevengi, not any of the BSA file openers from above.

If your file's suffix isn't ".BSA," research its real file extension to learn which programs can be used to open or convert it. You might even have luck opening the file as a text document with a free text editor.

More on BSA Files

The Elder Scrolls Construction Set Wiki has some useful information on BSA files including how to create your own.

You can read more about BSA files at The Garden of Eden Creation Kit (G.E.C.K.) from Bethesda Softworks. Also from G.E.C.K. is a page with information on advanced modding techniques for changing how the game works through altering the BSA files.

  • Which program do I use to create BSA files?

    The BSAOpt program allows you to package files into the BSA format. You can also go to the Nexus Mods website to use the BSArch command-line tool for packing and unpacking BSA files.

  • How do I merge BSA files?

    If you have multiple BSA files, open them individually, then use a program like BSAOpt to package all of the contents into a new BSA file.

  • What is a BA2 file?

    BA2 is another file format used by Bethesda games such as Fallout 4. BA2 files contain compressed data for 3D models and textures.

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