How to Clean Mozilla Firefox cache2 & startupCache
Location & Quick Verdict
%LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2
Firefox stores disk-cached images, compiled JS bytecode, and offline DOM storage in LocalAppData\Mozilla\Firefox\Profiles.
How Embedded Chromium (Electron / CEF) Caches Bloated Mozilla Firefox cache2 & startupCache
Modern web browsers and desktop apps built on Electron, Chromium Embedded Framework (CEF), or WebView2 run a full browser storage engine inside %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2. Every inline video preview, animated sticker, PWA offline bundle, and compiled V8 JavaScript script is written into disk-backed Cache_Data, Code Cache, Service Worker CacheStorage, and IndexedDB LevelDB tables without strict disk quotas.
Over months of daily usage, Mozilla Firefox cache2 & startupCache accumulates 1.0 GB – 6.0 GB of expired media blobs and stale Service Worker caches that are never evicted automatically. Clearing these cache subdirectories forces a clean storage state without deleting your saved passwords, active session cookies, bookmarks, or local databases.
# Inspect current disk footprint of Mozilla Firefox cache2 & startupCache (Read-Only)
$target = "$env:LOCALAPPDATA\Mozilla\Firefox\Profiles\*.default-release\cache2"
Get-ChildItem -Path $target -Recurse -Force -ErrorAction SilentlyContinue |
Measure-Object -Property Length -Sum |
Select-Object Count, @{Name="SizeGB";Expression={[math]::Round($_.Sum / 1GB, 2)}}
Manual Cleaning Instructions
- 1 Close Mozilla Firefox.
- 2 Press Windows Key + R, type %localappdata%\Mozilla\Firefox\Profiles and press Enter.
- 3 Open your profile folder and delete 'cache2' and 'startupCache'.
Note: If Windows alerts that a file is in use or locked by a background process, close the associated task in Task Manager before deleting, or use SWEEPR Cleaner to release locked handles safely.
Sub-Folders & Cache Locations Breakdown for Mozilla Firefox cache2 & startupCache
Modern Windows applications and system services split their disk footprint across multiple sub-directories (`Cache_Data`, `Service Worker\CacheStorage`, `Code Cache`, `GPUCache`, and `Crashpad\reports`). Review which sub-folders inside Mozilla Firefox cache2 & startupCache are safe to purge and which files remain protected:
| Sub-Folder / Cache Location | Storage Role | Typical Footprint | Deletion Safety |
|---|---|---|---|
| %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2\Cache\Cache_Data | HTTP Disk Cache, Web Bundles & Static Media Chunks | 1.0 GB – 6.0 GB | 🟢 100% Safe |
| %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2\Service Worker\CacheStorage | Offline PWA Assets, Background Sync & Media Blob Storage | 500 MB – 6.5 GB | 🟢 100% Safe |
| %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2\Code Cache\js & wasm | V8 Compiled JavaScript & WebAssembly Bytecode Cache | 250 MB – 2.5 GB | 🟢 100% Safe |
| %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2\GPUCache & DawnCache | Chromium Skia/ANGLE/WebGPU Compiled Shader Cache | 200 MB – 2.0 GB | 🟢 100% Safe |
| %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2\Crashpad\reports | Historical Process Minidump (.dmp) Telemetry Files | 150 MB – 3.0 GB | 🟢 100% Safe |
| Cookies, Login Data, Bookmarks & Local Storage (leveldb) | Active Account Sessions, Saved Passwords & User Preferences | Protected | 🔒 Protected — Never Touched |
Frequently Asked Questions
Is it safe to delete Mozilla Firefox cache2 & startupCache?
Yes, 100% safe. Frees up disk space immediately while keeping bookmarks, cookies, and extensions in Roaming AppData safe.
How much storage space will cleaning Mozilla Firefox cache2 & startupCache free up?
Users typically reclaim 1.0 GB – 6.0 GB on Windows 10 and Windows 11 systems depending on update frequency and active cache retention in %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2.
Will clearing Mozilla Firefox cache2 & startupCache sign me out of my accounts or delete my chat history?
No. Authentication tokens, cookies, and bookmarks live in separate profile files (such as Cookies, Login Data, and Local Storage). Cleaning the cache subfolders inside %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2 only removes temporary media and script caches.
Where is Mozilla Firefox cache2 & startupCache located on Windows 10 and Windows 11?
It is stored at %LocalAppData%\Mozilla\Firefox\Profiles\*.default-release\cache2. You can paste that path directly into the Windows Run dialog (Win + R) or File Explorer address bar to inspect it.
Manual File Explorer vs. 1-Click SWEEPR Cleanup
| Feature | Manual Deletion | SWEEPR Cleaner |
|---|---|---|
| Locked File Handling | Fails on locked processes | Safe background release |
| Accidental Deletion Risk | Moderate (easy to delete wrong folder) | Zero (strict rules & hashes) |
| Safety Undo Rollback | None (Shift+Del is permanent) | 7-Day Automatic Rollback |
| Time Required | 10–20 minutes per app | < 60 seconds across 40+ areas |
Related Windows Cleanup Guides & Hidden Space Hogs
Clean Mozilla Firefox cache2 & startupCache Automatically
SWEEPR Cleaner safely clears Mozilla Firefox cache2 & startupCache along with 40+ other hidden app folders and leftover files in one click—covering up to 5 devices (Windows, Mac, Android & iOS) with a 7-day undo safety net.