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Phyrox ESR portable app made with Portapps.
Run Mozilla Firefox ESR as a portable app.

Latest version 115.10.0
Internal release 63
Last updated 2024/05/05
Maintainer CrazyMax
License Mozilla Public License 2.0


Download and install the latest portable setup where you want then run phyrox-esr-portable.exe.

If you have already installed Firefox ESR from the original setup, move the following files :

  • %APPDATA%\Mozilla\Firefox\Profiles\*.default\* to data\profile\default

Then run phyrox-esr-portable.exe and remove Firefox ESR from your computer.


For an upgrade, simply download and install the latest portable setup.


Following a trademark violation report (#5) from Mozilla, Firefox ESR portable has been named Phyrox ESR portable on Portapps. Nothing changes except its name.

Standard and Developer Edition are also available


Some modifications have been made through policies to ensure portability:

  • Multilingual : All languages are included in app\langs and can be enabled in config file (see below).
  • Disable updater : Firefox ESR updates are turned off.
  • Don’t check default browser : Stops Firefox ESR from checking if it is the default browser at startup.
  • ‘Know your rights’: Don’t show on first run.
  • WhatsNew: Don’t show WhatsNew on first run after every update.
  • Profile: Profile path is overrided to data\profile folder (see below).
  • A shortcut is created at launch to allow native notifications and removed when Firefox is closed


Phyrox ESR portable can be configured through the main YAML configuration file:

  profile: default
  multiple_instances: false
  locale: en-US
  cleanup: false
  • profile : Name of the profile created in data\profile\<name> (default default)
  • multiple_instances : Allow multiple instances (default false)
  • disable_telemetry : If enabled, Firefox ESR telemetry is not uploaded (default false)
  • disable_firefox_studies : If enabled, Firefox ESR will never run SHIELD studies or do Heartbeat surveys. (default false)
  • locale : Locale located in app\langs can be used to change UI language without .xpi extension (default en-US).
  • cleanup : Cleanup leftover folders (default false)


You can use custom policies by creating data/policies.json file like this one:

  "policies": {
    "DisableFirefoxStudies": true,
    "DisableTelemetry": true

DisableAppUpdate and DontCheckDefaultBrowser are forced to true.

Known issues

There is no known issues Please let us know if you found one!


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