Mobile device users often encounter folders and files whose purpose remains a mystery. One of the most common questions is the nature of files with the extension .obb. This data takes up a significant amount of internal memory, causing anxiety among smartphone owners: can they be deleted, why you need them, and how to work with them. The short answer is simple: these are containers with additional data for applications, most often for games.
In the modern ecosystem Google Play there is a limit on the size of a single APK installation file. To allow developers to produce projects with high-quality graphics and extensive content, the system allows you to move “heavy” resources into separate OBB files. Understanding their structure will help you wisely manage the space on your gadget's drive.
Many people mistakenly believe that deleting these files will free up space without consequences. However, this will cause the application to stop running or require gigabytes of data to be downloaded again. In this article we will analyze in detail the technical side of the issue, access paths to system folders and methods for managing this data.
Technical purpose and storage structure
The abbreviation OBB stands for Opaque Binary Blob. This is a binary container, which is essentially an archive. It stores textures, models, audio tracks, music and videos necessary for the application to work. The division into APK (executable code) and OBB (resources) allows the store to update the app itself without requiring the user to download all game assets again.
There is a strictly defined place in the Android file system to place this data. By default, the system creates a path /Android/obb/ at the root of the internal storage. Inside this directory, each app has its own subfolder, the name of which corresponds to the package name of the application, for example com.rockstargames.gtasa. Violation of this hierarchy will lead to reading errors.
It is worth noting that starting from version Android 11, Google's security policy has become more stringent. Direct access to a folder /Android/obb/ through standard file managers is now often limited. This is done to protect user data and prevent third-party applications from interfering with system processes.
If your file manager does not see the Android folder, try using the built-in Files by Google explorer or specialized utilities like Solid Explorer, which require special permission to access system directories.
⚠️ Attention: OBB files are tied to a specific version of the application. If you update your game through the store, the old OBB file may become incompatible and the application will automatically request to download a new version of the assets.
Why do games use separate containers
The main reason for using this format is due to platform limitations Android. Historically, the size of an APK file uploaded should not exceed 100 MB (although these limits have been revised in recent years, the principle remains). AAA projects with photorealistic graphics weigh several gigabytes, making a single installation file impossible.
In addition, data separation simplifies the update process. Imagine the situation: the developers fixed a bug in the game code, but did not change the graphics. If a single file were used, the user would have to download the entire volume of the game again. Using OBB, only a small APK file is updated, and heavy resources remain in place.
There are several types of files that are packaged in this container:
- 📦 Graphics assets: high-resolution textures, interface sprites, 3D character models.
- 🎵 Media content: background music, sound effects, voice acting of dialogues in different languages.
- 🎬 Video inserts: startup screensavers, in-game cutscenes and training videos.
- 🗺️ Maps and levels: data for procedural generation or pre-created locations in strategies.
The use of external extensions also allows implement paid add-ons (DLC). The developer can release the basic version of the game, and distribute additional content in the form of a separate OBB file, which is downloaded only after purchase.
Instructions for manual transfer to a memory card
Owners of smartphones with a small amount of built-in memory often try to transfer OBB files to a microSD card. Although modern versions of Android restrict apps from working with external memory, manual transfer via a computer or an advanced file manager is still possible for many devices.
Before starting the procedure, make sure that your memory card is formatted as a portable drive and not as part of the internal memory (unless you want to lose data when changing the card). The process requires attention to access paths.
☑️ OBB transfer algorithm
First you need to let the application create the desired structure. Launch the game, wait for the data to load, and then close it. Now connect your device to your computer via a USB cable. Find the folder Android/obb in the internal storage. Inside you will see a folder with the package name, for example com.ea.game.pvz2_row.
Copy this entire folder. Then go to your memory card (usually shown as a separate drive or partition). Create a path there Android/obbif it does not already exist, and paste the copied folder. After this, you can delete the original from the internal memory of the smartphone.
Source: /storage/emulated/0/Android/obb/com.package.name/
Target: /storage/sdcard1/Android/obb/com.package.name/
⚠️ Attention: Not All applications support launching from a memory card. Some games are hard-coded to only look for resources in internal storage. In this case, the game will throw an error at startup, and the files will have to be returned.
Frequent problems and errors when working with OBB
The most common problem is the message “Failed to verify license” or endless loading when starting the application. Most often this is due to a violation of the integrity of the files or an incorrect path to them. Even one missing letter in the folder name can be fatal.
Another situation arises when updating the system or resetting the settings. If you manually transferred files, the system may "lose" the connection between the application and its data. In this case, a re-check of the paths or a complete reinstallation of the content is required.
Consider the main causes of failures in the table below:
| Symptom | Probable cause | Solution method |
|---|---|---|
| Black screen when startup | Missing file main.obb | Check for the file in the obb folder |
| Request to download data | APK and OBB versions do not match | Update the application through the store |
| Game crashes after 5 seconds | Damage to the archive when copying | Copy the file again |
| Google license error | Invalid folder package name | Check the name with the APK name |
What to do if the game requires internet for verification?
Some games use OBB to protect against piracy. When first launched, they check the hash sum of the files with the server. If you changed the file manually, the verification will fail. In such cases, only a clean installation from an official source helps.
It is also worth considering the speed of the memory card. If you transferred a heavy game to an old card of class 10 or lower, textures may be delayed in loading, causing stuttering and stuttering gameplay. For modern projects, it is recommended to use standard cards UHS-I or higher.
Is it possible to delete OBB files to save space
The question of deleting these files arises for everyone who sees how the smartphone’s memory is rapidly filling up. The answer depends on whether you are currently using the application. If you no longer need a game or app, deleting the folder with its name in the OBB directory is completely safe.
However, if you plan to play in the future, deleting it will require you to re-download several gigabytes of data. This will not only take time, but also consume traffic if you do not have unlimited Internet. Cache files are not temporary in the usual sense, they are a full-fledged part of the app.
Sometimes users find “orphaned” OBB folders from long-deleted applications. This happens if the app was uninstalled incorrectly or if there are tails left after a system reset. In this case, you can safely delete folders whose names mean nothing to you, having first checked the list of installed applications.
You can safely delete OBB files only if the corresponding application has already been removed from the system or you know for sure that you will never need it again.
To identify unnecessary data, you can use the storage analysis function in the Android settings. The system will show which application takes up the most space. If you see a game that you haven't played for six months, deleting it along with the OBB container will free up a significant amount of space.
Corrupted data recovery and alternatives
In situations where the OBB file is damaged (for example, due to a sudden power outage while copying), the game will not launch. A standard recovery mechanism is often built into the application itself: if an integrity error is detected, it will offer to download the data again.
If the automatic download does not work, you will have to act manually. Delete the problematic file from the folder /Android/obb/ and clear the application cache through the system settings (Settings → Applications → [Game name] → Storage → Clear cache). After this, launching it again should initiate a fresh download.
There are alternative ways to obtain data, for example, through the "Download Extension" function in some launchers or using specialized download managers. However, the most reliable source is always the official application stores, as they guarantee compliance with the APK version and the OBB version.
⚠️ Attention: Downloading OBB files from third-party forums and torrent trackers carries the risk of infecting your device with viruses or receiving modified code. Use such sources only at your own peril and risk, having first scanned the file with an antivirus.
In some cases, renaming the file helps. If you downloaded a file named main.123.com.game.obb, and the application is looking for main.124.com.game.obb, simply changing the number in the name can solve the problem if the changes in resources were minor.
Is it possible to combine APK and OBB into one file?
Technically this is possible using Google's bundletool tool, which creates the .apks or .aab. However, for the end user, installing such files is more difficult than a standard APK. Regular Android installers do not know how to unpack and install the APK+OBB bundle “on the fly” without the participation of the Play store.
Why did OBB files disappear after an Android update?
When a major system update or change of Android version, sometimes access rights are reset or the file system structure is changed. It is also possible that the updated application requires a new version of the resources, and the old one was automatically marked as outdated. Check the obb folder - most likely, there are files there, but the application does not see them because the paths have changed.
How much can one OBB file weigh?
The size of an OBB file does not have a hard limit on the part of the file system, but it is logically limited by the size of the available memory of the device and the user’s patience for downloading. There are files ranging in size from 50 MB to 4-5 GB. Some games use several OBB files (main and patches), which in total can take up more than 10 GB.
Does transferring OBB to a memory card affect the speed of the game?
Yes, it does. The read speed of the internal memory (UFS 2.1/3.1) is significantly faster than most microSD cards. Transferring heavy games to the card can lead to increased loading times for levels and slowdowns when loading textures. It is recommended to transfer only those games that are not critical to disk speed, or use memory cards of the highest speed class.