# Firefox

## AddOn

- MultiLogin: addons.mozilla.org/addon/multi-account-containers

## Disable 'Reset Firefox ...'

- Tired of annoying mesage "It looks like you haven't started Firefox in a while. Do you want to clean it up for a fresh, like-new experience? And by the way, welcome back!"
- Solution found at [http://miroslav.suchy.cz/blog/archives/2014/05/13/how\_to\_disable\_reset\_prompt\_in\_firefox/index.html](http://miroslav.suchy.cz/blog/archives/2014/05/13/how_to_disable_reset_prompt_in_firefox/index.html)
- step by step: 
    - Open: `about:config`
    - Create a new entry by `selecting any entry > right mouse click > New > Boolean`
    - Enter the preference name: `browser.disableResetPrompt`
    - Value: `True`

## This Connection is Untrusted

[![ff1.png](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/ff1.png)](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/ff1.png)

- You see this message on encrypted sites with selfsigned certificates. If you trust the site, click:

```
I Understand the Risks > Add Exception > Get Certificate > Confirm Security Exception

```

## Profile in use / Clean lock files

- After an unclean stop of Mozilla or Thunderbird (application crashes, desktop session crash, server crash ) it happened frequently that a new start of the application fails with:

[![inuse.png](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/inuse.png)](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/inuse.png)

- To clean the setup, start either 
    - `Menu: Repair+Clean Firefox` or
    - call `clean-firefox.sh` from a terminal.

## Turn off Spell Checker

`Tools > Options > Advanced > General > Check my spelling as I type: Off`

## Firefox Not Scrolling with Up/Down Arrow Keys or Home/End Keys

- Hit **F7** to activate/deactivate 'caret browsing'
- [http://en.wikipedia.org/wiki/Caret\_navigation](http://en.wikipedia.org/wiki/Caret_navigation)

## Export / Import Bookmarks

This section explains how to export your bookmarks i.e on Windows to an HTML file, which can be used as a backup or for importing into another web browser and/or on an different Plattform.

### Export

- Click the Library button |||\\ icon, then click Bookmarks. Scroll to the bottom and click Show all Bookmarks.
- From the toolbar on the Library window, click Import and Backup and choose Export Bookmarks to HTML
- In the Export Bookmarks File window that opens, choose a location to save the file (any place you have write access will work), which is named bookmarks.html by default.
- Click the Save button. The Export Bookmarks File window will close.
- Close the Library window

### Import

- Click the Library |||\\ icon, then click Bookmarks. Scroll to the bottom and click Show all Bookmarks.
- From the toolbar on the Library window, click Import and Backup and choose Import Bookmarks from HTML
- In the Import Bookmarks File window that opens, navigate to the previously saved bookmarks HTML file you want import
- Click the Open button. The Import Bookmarks File window will close.
- Close the Library window. 
    - The bookmarks in the selected HTML file will be added to your Firefox bookmarks within the Bookmarks Menu directory.

## Cookies

Cookies are small files stored by Firefox that contain website-related data. Sometimes it is necessary to clean then if some page does not open correctly.

- Open the settings menu

[![firefox-menu-settings.png](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/firefox-menu-settings.png)](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/firefox-menu-settings.png)

- Choose *Privacy & Security* tab and scroll down to the *Cookies and Site Data* section

[![firefox-settings-cookies.png](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/firefox-settings-cookies.png)](https://wiki.math.uzh.ch/public/uploads/images/gallery/2026-06/firefox-settings-cookies.png)

Here you can delete all cookies or cookies from selected pages. Several time periods are provided

- short-time periods (last hours, this day) are perfect to clean recent sessions
- in case of problems it is best to choose **Everything**