Important Notice: We're experiencing email notification issues. If you've posted a question in the community forums recently, please check your profile manually for responses while we're working to fix this.

On Monday the 3rd of March, around 5pm UTC (9am PT) users may experience a brief period of downtime while one of our underlying services is under maintenance.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Firefox 33 will not retain customizzation settings

  • 1 reply
  • 2 have this problem
  • 2 views
  • Last reply by cor-el

more options

After changing homepage and installing themes, Firefox 33 resorts to default settings on subsequent startup.

After changing homepage and installing themes, Firefox 33 resorts to default settings on subsequent startup.

Chosen solution

If you do not keep changes after a restart or otherwise have problems with preferences, see:

The data of all installed lightweight themes (Personas) and its background color and text color is stored in the lightweightThemes.usedThemes pref in JSON object format ({"id":"#","name":"xxx",...}).


There is software like Advanced SystemCare with its Surfing Protection feature that can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

Read this answer in context 👍 0

All Replies (1)

more options

Chosen Solution

If you do not keep changes after a restart or otherwise have problems with preferences, see:

The data of all installed lightweight themes (Personas) and its background color and text color is stored in the lightweightThemes.usedThemes pref in JSON object format ({"id":"#","name":"xxx",...}).


There is software like Advanced SystemCare with its Surfing Protection feature that can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.