How to Work Offline in Mozilla Firefox

Enabling Offline Mode

Understand how Offline Mode works. Offline Mode removes Firefox's connection to the internet, instead fetching all information from the browser cache. While online, Firefox will automatically save websites you browse as cached web content. These cached versions of the sites can be accessed when offline, but additional browsing beyond the saved content is not possible (i.e. you can navigate to any site you previously visited, but any links on that site that are not already cached will return an error. Likewise, even if connectivity is restored, Offline Mode must be disabled to resume browsing non-cached sites). The storage size of the cache is limited. As a user browses, older content is removed from the cache and replaced with the most recent. By default, Firefox stores a cache of 350MB. This is a solid amount of web content, but if you want more (or less), you can edit the cache size by going to “☰ > Options > Advanced > Network” and selecting “Override automatic cache management”. This will allow you manually set the cache size.

Go to Firefox Settings. Press ☰. This opens a menu with various options for Firefox.

Click on the More option from the drop-down menu.

Enable Offline Mode. Select "Work Offline" at the bottom of the list. A check will appear next to the menu option indicating that it is active. You can now browse cached pages.

Browse cached sites. You can visit recently visited sites, depending on your browsing habits and cache size. Go to "☰ > History” to see what is available to visit.

Disabling Offline Mode

Understand the reason for disabling Offline Mode. Offline mode disables Firefox's ability to communicate with the internet. When internet access is restored, you must disable Offline Mode in order to use your browser normally again. Attempting to browse non-cached pages on the web while in Offline Mode will return an error, even if your internet connection is working.

Go to Firefox Settings. Press ☰. This opens a menu with various options for Firefox.

Open the Developer menu. Press "Developer". This will open a menu with various developer tools, including Offline Mode.

Disable Offline Mode. Select "Work Offline" at the bottom of the list. The check next to the menu option will disappear indicating that the feature is now disabled.

Browse the internet normally. You can now browse the internet without receiving an error. Visiting webpages will now display the live version instead of the cached one.