It only takes a couple of steps to clear the cache on the desktop version of Firefox, as explained by Mozilla on its support website. Before following these steps, make sure to backup any website login credentials you may not have memorized already; this can be done by, for example, saving them in a password locker like LastPass or in Firefox’s own password manager. Once your usernames and passwords are safe, follow these steps to clear the cache in Firefox on Desktop.
1. Open Firefox and click on the “Application Menu” button in the top right corner of the browser next to the address bar.
2. Click on “Settings” in the menu that opens.
3. Click on “Privacy & Security.”
4. Under “Cookies and Site Data,” click on “Clear Data.”
5. There are two options you can check depending on the data your want to clear. The first option is “Cookies and Site Data.” If this option is checked, you’ll be signed out of any websites you’re logged into and you’ll need the sign-in credentials to log back in. To fully clear your cache, you’ll want to check this option, but you can try selecting “Cached Web Content” only first to see if that alone fixes your problem.
6. Click on “Clear” to delete the data.
It’ll take a moment or two, but all of your cached browser data will be cleared. It may be a better option to avoid clearing cookies and site data initially to see if clearing only web content solves your issue, but fully clearing all cached data will be necessary in some circumstances.