Windows
Compatible applications
Quick Facts
Basic information about this file format
Extension
.OBB
File Type
Opaque Binary Blob
Category
Data
Best first step
Use compatible software
Quick Summary
A practical overview of the .obb file format
An OBB file is an expansion file used by the Android operating system to store additional data for applications. Because Android application packages (APKs) are limited in size, developers often use OBB files to store large assets such as high-resolution graphics, media files, and other large data…
File extension
.OBB
File type
Opaque Binary Blob
Category
Data
Recommended action
Open with a trusted compatible app
How to open a .obb file
Start with a trusted app that supports this format
- Check the file extension carefully and confirm that the file name really ends with .obb.
- Use software that supports this file type. If one app does not work, try another compatible program for the same platform.
- Update the application if the file was created by a newer version of the software.
- Scan files from unknown sources before opening them, especially documents, archives, scripts, installers, and executable files.
What is a .obb file?
File extension details and usage information
An OBB file is an expansion file used by the Android operating system to store additional data for applications. Because Android application packages (APKs) are limited in size, developers often use OBB files to store large assets such as high-resolution graphics, media files, and other large data that are essential for the application to function correctly. These files are typically downloaded separately from the main APK and stored on the device's external storage or in a designated location within the internal storage. OBB files are usually encrypted or obfuscated to protect the application's assets from unauthorized access or modification. They are often used for games with extensive textures and audio, or applications with large amounts of pre-rendered content. The Android system provides APIs for accessing and managing OBB files, allowing applications to seamlessly integrate the data stored within them. The OBB file format itself is essentially a ZIP archive, often containing multiple files and directories organized in a specific structure that the application expects. When the application needs to access the data, it uses the Android APIs to mount the OBB file and access its contents as if they were part of the application's file system.
Software Compatibility
Programs that may open or work with .obb files
macOS
Compatible applications
Linux
Compatible applications
Mobile
Mobile applications
Can .obb files be converted?
Options for saving or exporting this file to another format
In many cases, a .obb file can be converted by opening it in compatible software and using an option such as Save As, Export, or Convert. The available output formats depend on the file type and the application used.
- Use the original software that created the file when possible.
- Check whether the application supports exporting to common formats.
- Be careful with online converters when working with private, business, or sensitive files.
- If conversion fails, the file may be corrupted, incomplete, encrypted, or not actually a .obb file.
Why can't I open a .obb file?
Common reasons this file type may not open correctly
Wrong software
The file may require a specific program that supports the .obb format.
Incorrect extension
The file extension may have been renamed manually, even though the actual file format is different.
Corrupted file
The file may be incomplete, damaged during download, or transferred incorrectly.
Outdated app
Your software may need to be updated before it can open newer versions of this file format.
Frequently Asked Questions
Common questions about .obb files
To open a .obb file, use software that supports this file format.
- Android Studio
- 7-Zip
- WinRAR
- PeaZip
- The Unarchiver
Open the file in compatible software and look for options such as Save As, Export, or Convert. If no export option is available, the file may require a specialized converter or the original application that created it.
- Verify that the file extension is correct.
- Install or update compatible software.
- Try another application that supports this format.
- Check whether the file is corrupted, incomplete, or encrypted.
A file extension alone does not guarantee whether a file is safe or unsafe. Only open files from trusted sources, scan unknown files before opening them, and be especially careful with executable, script, archive, and document files.
File safety tips
Use caution with unknown files
Only open files from trusted sources. Before opening a .obb file, scan it with antivirus software, verify that the file extension is expected, and avoid running unknown executable, installer, macro-enabled document, or script files.