If you thought uninstalling Firefox removes every trace of the browser, think again — extensions, plugins, cache and full user profiles are often left behind by design, and these leftover files can linger in hidden folders across Windows, macOS, and Linux. This feature-length guide shows exactly where Firefox leaves data, how to find and safely remove Firefox plugins after uninstalling the browser, and what to watch for so a future reinstall is truly clean.
Background
Firefox intentionally preserves user profiles and personal data when you remove the application. That behavior is helpful for users who plan to reinstall or migrate their settings, but it also means that extensions, plugin files, cached resources and profile data can remain on disk after the standard uninstall process completes. Mozilla’s own documentation clearly states that uninstalling Firefox does not erase user profiles or browsing data unless those folders are explicitly deleted. Community troubleshooting threads and veteran Windows support posts confirm the same advice: removing program binaries through Control Panel or an app-store uninstall often leaves AppData or Library profile directories untouched, and many users rely on manual folder removal or specialized uninstallers to remove leftovers.This article covers the locations and step-by-step removal procedures for Windows, macOS, and Linux; explains system-wide plugin locations; examines third‑party cleanup tools; flags risks (data loss, registry editing, permissions issues); and offers preventive measures to avoid future plugin buildup. Technical claims and folder locations are verified against official Mozilla guidance and other system documentation where available.
Why Firefox leaves plugins and profiles behind
Firefox’s uninstall behavior is intentional: the installer removes program files but keeps user profiles so bookmarks, saved passwords, add‑ons and customizations survive an uninstall/reinstall cycle. This is beneficial in many cases — but it means that uninstalling Firefox is not the same as a full clean removal.- The browser binary and Program Files folders are removed by the uninstaller.
- The profile folders — which contain extensions, cookies, passwords, caches and site data — are stored in user-specific locations and are left intact unless removed manually.
- System-wide plugins and helper files (legacy NPAPI or external helper apps) can be installed in OS-specific system folders and may remain after uninstall. Community guides often instruct users to check Program Files and system plugin directories for leftover components.
Overview: where Firefox keeps data (by OS)
Knowing the exact locations is the fastest route to a clean uninstall. The following overview lists the most common locations for profiles, cached data and system-wide plugins.Windows
- User profiles and extensions: C:\Users\<YourUser>\AppData\Roaming\Mozilla\Firefox\Profiles\ and the parent folder C:\Users\<YourUser>\AppData\Roaming\Mozilla\Firefox\ (profiles.ini lives in Roaming\Mozilla\Firefox).
- Local cache and other per-user Firefox folders: C:\Users\<YourUser>\AppData\Local\Mozilla\Firefox\ and C:\Users\<YourUser>\AppData\Local\Temp (temporary installer data may appear here).
- Program installation: C:\Program Files\Mozilla Firefox\ and on 64-bit systems possibly C:\Program Files (x86)\Mozilla Firefox\
- System-wide plugin or support folders can occasionally appear under C:\ProgramData\Mozilla\ or in Program Files entries; community posts recommend checking both program folders and ProgramData for leftovers.
macOS
- Main profile: ~/Library/Application Support/Firefox/ and specifically ~/Library/Application Support/Firefox/Profiles/
- Cache: ~/Library/Caches/Firefox/
- Preferences and preference plists: ~/Library/Preferences/org.mozilla.firefox*.plist
- System internet plug-ins: /Library/Internet Plug-Ins/ and ~/Library/Internet Plug-Ins/ may contain helper plugins.
Linux (including package and snap installs)
- Per-user profile: ~/.mozilla/firefox/
- Per-user cache: ~/.cache/mozilla/firefox/
- Snap install traces: ~/snap/firefox/ (if Firefox was installed via Snap on Ubuntu or similar) — Mozilla documentation calls out special behavior for snap installs where user data may be handled differently.
- System-wide install artifacts under /usr/lib/firefox or /etc/firefox may exist for manually installed or distribution-provided packages.
Windows: step-by-step — delete Firefox plugins after uninstall
The Windows path is the most common scenario. The following steps remove plugins, extensions, cached files and optional system-wide remnants after the Firefox application has been uninstalled.Preparation (mandatory)
- Back up anything you might want to keep: bookmarks (use the Bookmarks → Show All Bookmarks → Import and Backup → Export Bookmarks to HTML), password vaults (use a password manager or Firefox Sync), and any extension data you need.
- If Firefox is still installed, exit the program completely (Task Manager → End Task on any firefox.exe processes).
- Make sure hidden items are visible in File Explorer (View → Show → Hidden items) because AppData and Library folders are hidden by default. Community troubleshooting posts repeatedly warn users to unhide AppData before hunting for profiles.
Step 1 — Uninstall Firefox (if not done already)
- Control Panel → Programs and Features → select Mozilla Firefox → Uninstall.
- If installed from Microsoft Store, uninstall from Start → right-click Firefox → Uninstall instead. Microsoft guidance notes the difference in uninstall paths for Store and classic installs.
Step 2 — Remove user profile folders (extensions live here)
- Open File Explorer and paste or navigate to:
- %AppData%\Mozilla\Firefox\
- %LocalAppData%\Mozilla\Firefox\
- Delete the entire Profiles folder if the objective is a full wipe. Deleting Profiles removes bookmarks, history, passwords, cookies, and extensions. Use the Profile Manager or export bookmarks beforehand if needed. Mozilla explicitly documents that profile data stays unless removed by the user.
Step 3 — Clear caches and temp leftovers
- Remove %LocalAppData%\Mozilla\ and any Firefox folders inside %LocalAppData%\Temp or Windows Temp folders if present.
- Optionally run Disk Cleanup or Storage Sense to remove temporary install remnants (Windows built-in tools can help with safe temporary cleanup).
Step 4 — Check program and ProgramData folders (system-wide)
- Inspect C:\Program Files\Mozilla Firefox\ and C:\Program Files (x86)\Mozilla Firefox\ — if they still exist, delete them.
- Inspect C:\ProgramData\Mozilla\ for any leftover settings/plugins and remove as appropriate. Some plugin installers place files in ProgramData or in specific plugin folders.
Step 5 — (Optional, advanced) Registry cleanup — caution
- Only advanced users should edit the registry. Back up the registry first.
- Common places for Firefox keys are HKCU\Software\Mozilla and HKLM\Software\Mozilla (and the 32-bit equivalents on 64-bit systems).
- Use built-in uninstallers or a specialized tool (Revo Uninstaller) to scan for leftover registry keys if necessary. Community posts frequently recommend Revo to scan for leftover entries after an uninstall, but also warn to verify items before deletion.
macOS: step-by-step cleanup
macOS hides Library folders by default, so care is needed to reach the right locations.Step 1 — Remove the application
- Applications → drag Firefox to the Trash (or right-click → Move to Trash).
Step 2 — Delete Application Support and caches
- In Finder, choose Go → hold Option/Alt → Library.
- Delete ~/Library/Application Support/Firefox/ — this contains profiles and extensions. Mozilla’s uninstall guidance instructs deleting the Firefox folder under Application Support if a complete removal is desired.
- Delete caches: ~/Library/Caches/Firefox/ and any Firefox directories under ~/Library/Caches.
Step 3 — Remove preference files and plug-ins
- ~/Library/Preferences/org.mozilla.firefox*.plist — delete preference files to remove per-app settings.
- Check /Library/Internet Plug-Ins/ and ~/Library/Internet Plug-Ins/ for any browser-helper plug-ins or .plugin files and remove Firefox-related entries.
Step 4 — Empty the Trash and reboot
- Empty Trash to permanently remove files.
- Reboot to ensure any file locks are cleared.
Linux: step-by-step cleanup (including Snap)
Linux distributions vary, but the user profile and cache locations are fairly standard.Step 1 — Remove application package (prefer package manager)
- Ubuntu/Debian: sudo apt-get purge firefox*
- Fedora: sudo dnf remove firefox*
- Arch: sudo pacman -Rns firefox
Step 2 — Delete per-user Firefox directories
- rm -rf ~/.mozilla/firefox/
- rm -rf ~/.cache/mozilla/firefox/
- If installed as a Snap package: rm -rf ~/snap/firefox/ — Snap-managed installs keep data under the snap hierarchy and may require snap removal (snap remove firefox) followed by manual deletions if needed. Snap installs behave differently; Mozilla documentation notes that uninstalling via Snap may not remove user profile data automatically.
Step 3 — Remove system-wide remnants
- sudo rm -rf /usr/lib/firefox/
- sudo rm -rf /etc/firefox/
- Take care: removing distribution-managed files can break other packages; prefer package manager removal to raw deletion where possible.
Third‑party uninstallers and cleanup tools — practical advice
Third-party tools can speed up the search-and-delete process, but they come with tradeoffs.- Revo Uninstaller (Windows): runs the program’s uninstaller then scans for leftover files and registry entries. Widely recommended by community posts for stubborn leftovers but must be used carefully — always review items before deletion.
- IObit Uninstaller (Windows): offers “Powerful Scan” for leftovers; be cautious with registry cleaning features.
- AppCleaner (macOS): removes app bundles and tries to find associated support and cache files. It’s a reliable option for most users on macOS.
- For Linux: rely on package managers (apt, dnf, pacman, snap) and use purge/remove options for a safer outcome.
Advanced cleanup: system-wide plugins, helper apps and legacy NPAPI
Firefox dropped support for most NPAPI plugins long ago (except a limited Flash-era legacy). However, helper apps and third-party plugins can still install into system plugin locations or as background services.- Check the following system folders:
- Windows: C:\Program Files\Mozilla Firefox\plugins\ and C:\Program Files (x86)\Mozilla Firefox\plugins\; also check C:\ProgramData\ and system Program Files for third-party add-ons.
- macOS: /Library/Internet Plug-Ins/ and ~/Library/Internet Plug-Ins/
- Linux: /usr/lib/mozilla/plugins/ or similar distro-specific paths.
- Remove only clearly related plugin files. If a plugin is used by other browsers or software, removing it may break those apps.
- For signed or system services installed by other vendors (security suites, helper utilities), consult vendor documentation before deleting.
Safety, privacy and data-removal considerations
Deleting profile folders erases personally identifiable browsing data. In many cases the OS will mark deleted data as free space — it can still be recovered with forensic tools unless the disk space is overwritten.- For secure deletion: use OS tools that overwrite files (cipher /w on Windows, srm or shred on Linux, third-party secure-delete utilities) if the goal is non‑recoverability.
- For privacy: disconnect from Firefox Sync before deleting a machine-specific profile to avoid propagating deletions to other synchronized devices. Mozilla support warns that Sync can re-populate data if the account remains active.
- Always back up bookmarks and any data you might need later. Export bookmarks and export saved passwords if users plan to reinstall Firefox or move to a new profile.
Troubleshooting common problems
- “Files in use” or cannot delete: reboot into Safe Mode (Windows) or boot into Recovery/Single User (macOS/Linux) to delete locked files. On Windows, check Task Manager for firefox.exe and background processes; services or helper apps from third parties may hold files open. Community threads often advise stopping processes and retrying deletion.
- Reinstall doesn’t clear issues: a reinstall that restores the same profile will reinstate extensions and settings. Use a fresh profile or delete the profile folder before reinstalling if the goal is a clean start. Mozilla documents profile management and the Profile Manager workflow for creating or removing profiles.
- Snap installs behave differently: on Ubuntu and similar distros, Firefox packaged as a Snap may keep data under ~/snap/firefox/ and the Snap removal process can leave profile remnants. Remove Snap packages via snap remove firefox and then manually inspect the snap folder.
- Registry errors after uninstall: registry edits are risky. Create a system restore point before making changes or use a reputable uninstaller to scan and show leftover keys for manual review. Community advice is unanimous: don’t blind-delete registry entries.
Preventing future plugin buildup
- Use Firefox Refresh (Reset) before uninstalling: Firefox includes a “Refresh Firefox” option in about:support that removes extensions and restores defaults while keeping essential bookmarks and passwords. This is a good first step before an uninstall.
- Prefer portable installations for ephemeral browsing: Firefox Portable keeps all data in one folder and can be removed easily by deleting that folder.
- Periodic profile housekeeping: periodically inspect the profile folder and extension list; remove unused add-ons and use built-in Clear Data tools for site data.
- Use Firefox Sync responsibly: disconnect the device from Sync if the intention is to wipe local data only; otherwise Sync may re-provision data to a clean install.
Critical analysis — benefits, limitations and risks
Notable strengths of the manual cleanup approach
- Precision: manual deletion allows selective removal of only the unwanted files — profiles, caches or specific extensions — without touching other system components.
- Reversibility (with backups): exporting bookmarks and syncing data before deletion makes it possible to restore settings later.
- Low dependency: no third-party tools are required; standard file operations and package manager commands suffice.
Practical risks and tradeoffs
- Data loss: deleting the Profiles folder removes bookmarks, saved passwords and extension data permanently unless backed up. This is the most important risk and must be addressed with explicit backups.
- Registry and system modifications: registry edits and raw deletion of system folders can break other applications; those steps are for experienced users only.
- False sense of security: simple deletion does not guarantee secure erasure — deleted files can be recovered unless securely overwritten.
- Automated tools can misidentify shared components: third-party uninstaller tools help but are not infallible; they may suggest removing files used by other apps.
Where official documentation and community advice intersect
Mozilla support explicitly recommends manual profile removal when a complete data removal is intended, and community threads echo that recommendation while adding practical tips (show hidden folders, check ProgramData, use Revo for stubborn leftovers). Combining official instructions for profile locations with vetted community practice provides a reliable workflow.Claims that need caution
- Claims that leftover files “always” consume gigabytes should be treated cautiously — actual disk usage is user-specific. Run a folder-size check (right-click → Properties on Windows, du -sh on macOS/Linux) before deleting to quantify the impact.
- Some forum-sourced advice recommends aggressive registry cleaning tools that have caused problems for users; such recommendations should be vetted and performed only after creating a system backup or restore point.
Quick reference: safe checklist to delete Firefox plugins after uninstall
- Export bookmarks and backup passwords (or disconnect Firefox Sync).
- Uninstall Firefox via Control Panel / Applications / package manager / snap remove as applicable.
- Show hidden files and navigate to:
- Windows: %AppData%\Mozilla\Firefox\ and %LocalAppData%\Mozilla\Firefox\ — delete Profiles and leftover folders.
- macOS: ~/Library/Application Support/Firefox/ and ~/Library/Caches/Firefox/ — delete Firefox folders.
- Linux: ~/.mozilla/firefox/ and ~/.cache/mozilla/firefox/ — delete or use package manager purge.
- Inspect system plugin directories and Program Files / ProgramData for leftover installers and remove only what’s clearly Firefox-related.
- (Optional) Use an uninstaller (Revo/AppCleaner) but review items before final deletion.
- Empty Trash / Recycle Bin and reboot.
Conclusion
A single uninstall action does not guarantee a total removal of Firefox data. Extensions, plugin files, caches and profiles are intentionally preserved unless explicitly removed. The fastest, safest route to “delete Firefox plugins after uninstalling the browser” is a measured combination of official guidance (delete profile folders documented by Mozilla), careful manual inspection of OS-specific paths, and selective use of reputable cleanup tools when needed. Back up first, check folder sizes to avoid surprises, and avoid blind registry edits.For users seeking the cleanest removal: export bookmarks, sign out of Sync, uninstall the app, and then delete the profile and cache folders described above for your platform. That ensures the next installation starts with a blank slate — or that the disk space consumed by old extensions and caches is reclaimed. Official documentation and a breadth of community troubleshooting converges on those same steps, making this guidance reliable for typical Windows, macOS, and Linux environments.
Source: How2shout How to Delete Firefox Plugins After Uninstalling the browser
