Introduction
One of the most frustrating experiences for an Android user is seeing a “Storage Full” warning, only to find that the largest consumer of space is a mysterious category labeled “Other” or “System Data.” Unlike photos or apps, you cannot simply click on “Other” to see what’s inside. In 2026, with Android 15 and 16, this category has become even more complex as it includes AI model weights, high-resolution streaming caches, and system-level “Project Mainline” updates.
“Other” storage is essentially a catch-all for files that the Android system cannot easily categorize. This includes app logs, temporary extracted files, offline map data, and massive thumbnail databases. If left unmanaged, this section can easily swell to 20GB or 30GB, slowing down your device’s read/write speeds. This guide provides a technical roadmap to identifying these hidden files and reclaiming your storage without deleting your personal photos or apps.
1. Revealing the Hidden .thumbnails Folder
The single biggest “hidden” storage consumer in Android is the .thumbnails directory. Every time you open your gallery, Android creates a tiny preview of every photo and video. Over years of usage, this folder can grow to several gigabytes, even if you have deleted the original high-resolution photos.
To clear this:
- Open your File Manager (or “Files by Google”).
- Go to Settings and enable “Show hidden system files.”
- Navigate to Internal Storage > DCIM > .thumbnails.
- Delete everything inside this folder.Note: Your gallery might take a few seconds to load the next time you open it as it regenerates only the thumbnails you actually need.
2. Managing Social Media “Sent” Media
Apps like WhatsApp and Telegram are notorious for doubling your storage usage. When you send a 100MB video to a friend, WhatsApp keeps the original in your camera roll and creates a copy in its own “Sent” folder.
Use your file manager to navigate to:
- Android > media > com.whatsapp > WhatsApp > Media > WhatsApp Video > Sent
- Android > media > com.whatsapp > WhatsApp > Media > WhatsApp Images > Sent
Delete the contents of these “Sent” folders. You have already sent these files; there is no reason to keep a second copy hidden deep in your system folders.
3. Clearing “System Data” via App Cache Auditing
While clearing the cache of a single app is common knowledge, “System Data” often grows because of Streaming Apps (YouTube, Spotify, Netflix, Disney+). These apps cache “chunks” of video and audio to prevent buffering.
Go to Settings > Apps > See all apps. Sort the list by Size. Focus on your streaming and social media apps. Tap on each and select Clear Cache. Unlike “Clear Data,” this will not log you out of the app; it only removes the temporary video/audio fragments that have been categorized as “Other” storage.
4. Deleting Residual “OBB” and Data Files
When you uninstall a large game (like Genshin Impact or Call of Duty), Android sometimes fails to delete the associated “OBB” (Opaque Binary Blob) files. These are the massive 2GB-5GB files that contain the game’s graphics.
Navigate to Internal Storage > Android > obb. Look for folders belonging to games or apps you have already uninstalled. If you see a folder for a game that is no longer on your phone, delete the entire folder. This is a common “ghost” storage issue that standard cleaners often miss.
5. Cleaning Up “System Updates” and Log Files
In Android 15 and 16, the system occasionally downloads update packages in the background that are never fully cleared after installation. Additionally, if an app crashes frequently, it generates “Log” files.
- System Logs: Open your phone’s dialer and type
*#9900#(This works on many Samsung and Android devices). Select “Delete dumpstate/logcat.” This clears out system error logs that can take up hundreds of megabytes. - OTA Updates: In your file manager, search for a folder named “ota” or “downloaded_rom.” If you have already updated your phone, any files inside these folders are safe to delete.
6. Utilizing “Files by Google” AI Clean-up
Google has integrated powerful AI into the Files by Google app specifically to target “Other” storage. Open the app and go to the Clean tab.
- Look for “Delete Blurry Photos” and “Delete Large Files.”
- The “Junk Files” button specifically targets temporary app files, old installers (.apk), and log files that the system identifies as safe to remove.
7. Managing Telegram’s Aggressive Cache
Unlike WhatsApp, Telegram stores everything in the cloud but caches it locally as you scroll. If you are in many active groups, Telegram’s cache can reach 10GB+ in a single week.
Instead of using a file manager, open Telegram > Settings > Data and Storage > Storage Usage. Tap on “Clear Entire Cache.” You can also set the “Keep Media” slider to 3 days, ensuring that Telegram automatically deletes old cached files, keeping your “Other” storage under control permanently.
Conclusion
Reclaiming “Other” storage on Android is about knowing where the system hides its “paperwork.” By manually clearing the .thumbnails folder, auditing your social media “Sent” directories, and removing residual OBB files from uninstalled games, you can often free up significant space. In the modern era of Android 15 and 16, staying on top of these hidden folders is essential for maintaining a fast, responsive device and avoiding the dreaded “Storage Full” notification.