Modern operating-based smartphones systems Android are complex computing devices, where each app is isolated in its own space. Users often run out of internal memory or want to save game progress before resetting, but do not understand the physical structure of the file system. Understanding where application data is storedis the key to proper storage management and ensuring the security of personal information.
Android architecture is built on the sandbox principle, which means strict differentiation of access rights. System processes cannot arbitrarily read files of other apps without special permissions or superuser rights. This protects the user from malware, but complicates manual file management for advanced users who want to backup or transfer heavy caches to a memory card.
In this article, we will take a detailed look at the logical and physical structure of information storage, look at the differences between user data and the system cache, and also explore ways to access them through file managers and the computer. You will learn which directories can be cleared without the risk of losing important settings, and which directories are strictly not recommended to be touched without creating a backup.
Logical structure of the Android file system
The Android file system is based on the Linux kernel, which determines its hierarchical structure. For the average user, the visible part of the iceberg is the internal storage, which the system mounts as an accessible partition. However, hidden deeper are system partitions, access to which is closed by default. The main volume of user information resides in the section /data, which is divided into several critical subdirectories.
Each installed application receives its own unique user identifier (UID) and its corresponding directory. This provides isolation: the messenger cannot read the banking application database directly. Inside the protected area /data/data databases SQLite, settings files SharedPreferences and private app files are stored. Access to this path is only possible if you have root access or through debugging ADB.
In parallel with the protected area, there is public storage, often called “internal memory” or “SD card” in the Explorer interface. This is where applications save media files, downloads and cache, which is not critical for the operation of the app core. Understanding the difference between these two zones helps you avoid accidentally deleting an important configuration when clearing space.
⚠️ Attention: Directly editing files in system partitions without creating a backup copy can lead to applications not working or completely blocking the system boot (bootloop).
Before any manipulations with system files, use the "Backup" function in Google settings or specialized utilities like Titanium Backup (requires root).
Device internal memory and user partitions
When you connect your smartphone to a computer in file transfer mode (MTP), you see the root of the internal storage. Standard folders are located here, such as Download, Pictures, DCIM. However, a special directory is reserved for these applications Android. This is where most apps store their additional resources, map caches, music libraries and temporary files.
The folder structure Android is divided into two main subsections: data and obb. The directory Android/data contains files that are specific to each application, but can be cleaned by the user through the system settings. Deleting the contents of this folder usually resets the application settings to factory settings, but does not delete the account itself or progress if it is synchronized with the cloud.
The folder Android/obb is designed for storing large additional files (OBB - Opaque Binary Blob). This is typical for heavy games that cannot fit all the resources into one installation APK file. Textures, models and audio tracks are stored here. Transferring these files to a memory card is possible on some devices, but requires correct configuration of the paths in the system.
| Directory path | Data type | Access without Root | Risk of deletion |
|---|---|---|---|
/sdcard/Android/data |
Cache, logs, settings | Read/Write | Low (reset settings) |
/sdcard/Android/obb |
Game resources (textures) | Read/Write | Medium (the game will not start) |
/data/data |
Databases, logins | Root/ADB only | High (account loss) |
/data/app |
APK installation packages | Root only | Critical (deletion application) |
It is important to note that starting from version Android 11, Google has tightened the folder access policy Android/data. Third-party file managers can no longer freely view its contents without special permissions or using the system explorer. This change is aimed at increasing privacy, but has made life more difficult for users who are used to complete control over the file system.
System partition and protected application data
The most valuable information is stored in a hidden partition /data/data. Here are files that determine the status of your account in the application, the history of correspondence in instant messengers (if there is no cloud synchronization) and databases. Access to this partition is blocked for standard explorer applications for security reasons.
To access this data, the process of rooting the device or using USB debugging through a computer is required. The command adb pull allows you to copy the contents of a specific application folder to your computer for analysis or backup. For example, to save the database WhatsApp locally, you will need to run a command in a terminal with superuser rights.
adb root
adb pull /data/data/com.whatsapp/databases/msgstore.db /sdcard/backup/
This section also stores files SharedPreferences, which are XML files with simple settings: selected language, theme, switch state. Changing these files manually can lead to unpredictable behavior of the app, since it expects a certain data format.
⚠️ Attention: Modifying files in
/data/datamay break the digital signature of the application, which will lead to banking apps and payment systems refusing to work on the device.
Why banking applications do not work on rooted ones phones?
The SafetyNet mechanism (or Play Integrity API) checks the integrity of the system partition. If changes to system files or the presence of superuser rights are detected, the application blocks access to money transfer functions for the safety of your funds.
Application cache: purpose and clearing
Cache is temporary data that an application saves to speed up its operation. This includes downloaded images from social networks, temporary video files, and map thumbnails. The main purpose of caching is to reduce the load on the processor and network, so that when the content is reopened, it is loaded instantly from disk, rather than downloaded again.
Cache data can take up gigabytes of free space. For example, streaming services like Netflix or YouTube, as well as navigators like Yandex.Maps or Google Maps, actively use cache for offline access and fast scrolling of the feed. Clearing the cache is a safe operation: you will not lose your accounts, correspondence or progress in games, but the application may work a little slower when you first launch it after clearing.
- 🗑️ Clearing the cache frees up space, but does not delete the user's personal data.
- 🚀 When first launched after cleaning, the application will download data from the network, consuming traffic.
- ⚙️ The Android system automatically manages the cache size, deleting old files when there is insufficient memory.
Users can clear the cache both for individual applications through the settings menu, and globally through the "Storage" section. However, it is worth understanding that aggressive, constant clearing of the cache can lead to increased battery consumption, since the processor will have to process “heavy” content again more often.
Cache is a consumable item. Removing it is safe for personal data, but can temporarily slow down the application and increase the consumption of mobile traffic.
Transferring application data to a memory card
The issue of transferring applications to an external memory card (SD card) remains relevant for devices with a small amount of built-in storage. The "Move to SD card" function allows you to partially relocate application files to an external partition. However, it is important to understand that not everything is transferred: executable code and important system libraries often remain in the internal memory.
When an application is transferred to a memory card, it becomes dependent on the presence of this drive. If you remove the card or it fails, the app will no longer launch and widgets on your desktop may disappear. In addition, the speed of the app may decrease if a card of a low speed class is used (for example, Class 4 instead of UHS-I).
Some smartphone manufacturers allow you to format the memory card as internal storage (Adoptable Storage). In this case, the system encrypts the card and combines it with the main memory into a single pool. In this case, application data is stored on the card, but it will be impossible to read it on another device without formatting due to encryption keys.
☑️ Preparing to transfer applications
⚠️ Attention: When formatting the card as internal storage, all data on it will be permanently deleted. Make sure you save important photos and documents before starting the procedure.
Tools for analyzing and managing storage
To effectively manage disk space, it is not enough to simply delete files at random. There are specialized utilities that visualize the structure of occupied space. Built-in Android tools in the "Memory" section show general statistics, but third-party applications give a more detailed picture, showing the size of each folder in the form of a chart.
Popular tools such as Files by Google, DiskUsage or SD Maidallow you to find the largest files and folders. With their help, you can find forgotten downloads, duplicate photos, or large debug logs that take up space for months. The use of such analyzers helps to specifically free up space without deleting the necessary applications.
For advanced users, a computer with the package installed remains an indispensable tool. Android SDK Platform-Tools. Through the ADB console, you can get a list of all packages and the space they occupy with the command adb shell dumpsys package. This gives exact numbers in bytes, which are not always displayed correctly in the graphical interface of a smartphone.
- 📊 Visualization helps to quickly find memory “hogs” among old games.
- 🔍 Log analysis allows you to detect errors in applications that create giant text files.
- 🧹 Regular storage audits extend the life of the device's flash memory.
Use the "Free up space" function in the Google Files application - it automatically finds conversations, memes and large files that you have not opened for a long time.
Is it possible to recover deleted application data without a backup?
Restoring deleted data from a folder /data/data without a prior backup is almost impossible on modern devices. When an application is deleted, the system erases pointers to files, and FDE/FBE encryption makes restoring memory sectors meaningless without decryption keys, which are destroyed during a reset.
Why are some applications reset after updating Android?
When a major update to the operating system version (for example, from Android 13 to 14), the API structure or paths to system systems may change libraries. If the application developer has not updated its compatibility, the system can force clear the application data to prevent conflicts and errors in operation.
Where are passwords for applications on Android stored?
Passwords and authorization tokens are usually stored encrypted in the system key store (Android Keystore) or in database files internally /data/data. They are tied to a specific device and user, so simply copying files to another phone will not allow you to log into your account without re-authorization.
How to transfer game data to another phone?
The most reliable way is to use cloud synchronization through Google Play Games or a developer account (Facebook, VK). Local copying of folders obb and data can only work if both devices have the same version of the game and operating system, and the certificate signatures match.
Does filling up the memory affect the speed of the smartphone?
Yes, it has a critical effect. NAND flash memory used in smartphones significantly slows down writing and reading data when free space is less than 10-15% of the total capacity. This leads to interface lags, long opening of applications and failures when installing updates.