Browsers

Clear Mozilla Firefox Cache on Mac

To clear the Mozilla Firefox cache, use the built-in option in Settings, which removes only cached files and keeps your logins, cookies and history. Afterward, the app rebuilds the cache as you browse, so the first start may be a little slower.

Last updated: October 31, 20262 min read

Clear the Mozilla Firefox cache without guessing

Mozilla Firefox data usually takes 300 MB – 3 GB on a Mac. The free scan shows the exact size on your Mac before you change anything.

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Application: Mozilla Firefox
Typical data size: 300 MB – 3 GB
Category: Browsers
File Location: ~/Library/Application Support/Firefox

Clear it from inside Mozilla Firefox first

The safest way is the option built into the app: Settings > Privacy & Security > Cookies and Site Data > Clear Data; choose only the cached files option to keep cookies, logins and history.

Mozilla Firefox cache folders you can clear

These folders are rebuilt automatically, so removing them does not touch your own files.

~/Library/Caches/Firefox Cache · per-profile web cache Yes, rebuilt automatically~/Library/Saved Application State/org.mozilla.firefox.savedState Window state · window positions from the last session Yes, rebuilt automatically~/Library/Caches/Mozilla/updates Cache · downloaded Firefox updates waiting to be applied Yes, rebuilt automatically

Locations are the standard macOS folders Mozilla Firefox uses; some appear only after you use the matching feature.

What the Mozilla Firefox cache holds

Specific to Mozilla Firefox

The cache for Mozilla Firefox is the per-profile web cache, which keeps copies of pages and files so sites load faster on your next visit. Your profiles are separate: they hold bookmarks, history, passwords and add-ons in the Application Support folder, and clearing the cache leaves them alone. Clearing helps when sites keep showing stale versions, when the app starts slowly, or when the cache folder has grown large. Data for Mozilla Firefox typically takes 300 MB – 3 GB, so a large cache is a common reason to clear it.

What happens after you clear the Mozilla Firefox cache

Mozilla Firefox rebuilds the cache automatically as you browse, so nothing needs to be recreated by hand. The first start after clearing can be slower, because pages and files must be downloaded again. Cookies, logins and history are kept when you clear only the cached files, so you stay signed in. If you use a Mozilla account for sync, bookmarks, passwords, history, open tabs and add-ons stay synced and are not affected.

Open Settings in the app and go to Privacy & Security.Choose Clear Data under Cookies and Site Data, then select only cached files.Leave cookies, logins and history unchecked so you stay signed in.Restart the app afterward and expect a slower first start.

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Account and sync: A Mozilla account syncs bookmarks, passwords, history, open tabs and add-ons; profiles without sync exist only in the local Profiles folder.

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Frequently asked questions

Yes. Folders marked “Yes, rebuilt automatically” are rebuilt automatically; removing them only makes the next start slower.

Will the cache grow back if I do not clear it again?

Yes. The cache is rebuilt automatically as you browse, so it will gradually fill again over time.

Do I need to uninstall the app to clear the cache?

No. Clearing only the cached files is done inside the app, and your profiles stay where they are.