PortableApps.com - Firefox Portable

Frequently Asked Questions (Please Read)

John T. Haller — Fri, 14 Apr 2006 15:34:07 +0000

The most commonly asked questions about the use of Firefox Portable are answered on the main Firefox Portable support page. Please take a moment to look through it to see if your question is already answered before posting.

Forums:

Firefox Portable

random .parc files?

SGB74 — Sun, 18 Jan 2026 20:21:33 +0000

I'm not sure if this is the correct place to post this, but I've noticed when visiting a specific website neowin.net while using Firefox portable that there are three random .parc files that get written to the root directory of my drive. Is this something new, normal etc?

Forums:

Firefox Portable

problem ejecting USB drive after having run Firefox Portable from it

anonymous_person — Wed, 24 Dec 2025 05:42:34 +0000

So a while back I noticed that Windows was unable to eject my USB drive. I tried to use programs to find open handles or programs that might be open but it didn't help. I even bought and tried the program USB Safely Remove but it didn't help either. I did however find the cause to be Firefox Portable. I have tried with different USB sticks and also Firefox ESR. Here are the approximate steps I've done:

1. Put a fresh copy of Firefox Portable on the USB drive
2. Run Firefox Portable and browse websites for a few minutes
3. Exit Firefox Portable and wait a few minutes to give it time to fully close
4. Attempt to eject my USB drive and watch as it fails

This is very frustrating and makes it useless for me as it means I have to reboot the Windows computer or just remove USB drive without ejecting and hope no data gets corrupted. I am wondering if anyone else can reproduce this? Could it be related to my computer? I did try different USB ports too.

Forums:

Firefox Portable

Firefox 144.0.2, various sites not loading.

endell esq — Tue, 18 Nov 2025 23:33:20 +0000

I've just upgraded to Firefox 144.0.2 from 140.0.4.

Whereas 140.0.4 is working fine, since upgrading there are various sites not loading such as Facebook and Virus total.

Starting with 141.0.3 the web pages are not loading.

Any thoughts on this please? I've tried adjusting various setting but I'm having no luck.
Consequentially I'm having to run the older version

Thanks

Forums:

Firefox Portable

Cannot make FirefoxDE to run when modifying the executable & ini

ANONS — Thu, 23 Oct 2025 20:51:14 +0000

I changed "firefox.exe" inside the App\Firefox64 to "firefoxde.exe" & at same time modified the launcher configuration file inside Other\Source, the FirefoxPortable.ini, I looked for the line: "FirefoxExecutable=firefox.exe" and modified it to "FirefoxExecutable=firefoxde.exe"

I'm aware some programs don't like to be renamed, but I believe it was around 2 days ago that I saw a post that was quite old and it was stated it was possible for Firefox, but I get the error by the launcher, which is not able to find the executable.

Forums:

Firefox Portable

Tutorial Firefox Portable

Taiclaw — Tue, 21 Oct 2025 10:11:34 +0000

Can someone give a complete Tutorial to produce a Firefox Portable?

Forums:

Firefox Portable

Linux Firefox Portable

Taiclaw — Mon, 20 Oct 2025 02:18:29 +0000

Hallo

Is someone able to create a Firefox Portable for Linux, if possible without AI-Functions!

Forums:

Firefox Portable

Firefox legacy 115 updates

Thankalot — Thu, 16 Oct 2025 23:46:10 +0000

Hello,

I was wondering if you would continue to update it since they have extended the updates.

https://support.mozilla.org/en-US/kb/firefox-users-windows-7-8-and-81-mo...

Thank you.

Forums:

Firefox Portable

Read-only location - Profile folder locked - ESET Browser Protection

kimon — Thu, 25 Sep 2025 18:20:22 +0000

I just found the solution to this upsetting problem, thus I am sharing the relevant information with the community.

To solve all these issues, you have to disable ESET Browser Protection for all browsers, which is the second option underneath the Enable Safe Banking & Browsing option in the ESET configuration settings.

ESET - Setup - Advanced Setup - Browser Protection - Safe Banking & Browsing - Enable Safe Banking & Browsing - Browser Protection - Secure All Browsers

Please comment if you are also experiencing the following issue, and consider informing affected users in relative communities.

Under Windows 10/11, protected by ESET Internet Security (and probably all other ESET products), the default settings for ESET Browser Protection messes up with Firefox installations, as also with the automatic and non-automatic Firefox update mechanism, either when using the background update service or just the temporary background update "service", installed under ProgramData.

When you have enabled ESET Browser Protection for all browsers, it locks Firefox related folders over Windows 10/11 installations, including the profile folders, both for the main installation, under "%AppData%\Mozilla\Firefox\Profiles", as also for all portable installations, under their respective folders, and the background update service folder under ProgramData, namely "%ProgramData%\Mozilla-1de4eec8-1241-4177-a864-e594e8d1fb38", used by both the main installation and all portable installations.

For each one of the Firefox installations, whether it is the main installation or any portable installation, the corresponding folder locking happens the first time you run Firefox after enabling ESET Browser Protection for all browsers, and stays permanent in the system until disabling ESET Browser Protection for all browsers, where all locking information gets flushed immediately.

While Firefox can access these folders (update: not any more), for all other applications, even if Firefox is not running, you cannot access any file inside the locked folders, and if you try to copy or rename any of the files or their parent folders, you get a prompt for administrator permission, then a prompt from your own user account permission, which finally leads to an underlying access denied error.

It seems that with recent Firefox versions, even Firefox Portable cannot access these folders, thus it displays a message about appearing to be running from a location that is read-only.

Under Windows Safe Mode, where ESET does not run in the background, you can access all these files and folders, copy, rename, and delete them, but the frustrating part is that upon restarting in Windows Normal Mode, the above behavior continues, and the even worse part is that any folders being deleted under Windows Safe Mode are somewhat still locked, because if you try to create a New Folder and name it exactly as a deleted one, you get a prompt for administrator permission, then the folder gets created, but it immediately gets locked.

This malfunction heavily affects the update mechanism, for the main installation and any portable installations, causing immediate crashes upon loading, requiring having to restart in Windows Safe Mode, and manually deleting the Mozilla folder under ProgramData, in order to restore normal Firefox operation.

If you enable ESET Browser Protection for all browsers, you can see that you cannot rename the folder "Profiles" under "%AppData%\Mozilla\Firefox\", as well as the folder "User Data" under "%LocalAppData%\Google\Chrome\", thus this seems to be the browser protection approach by ESET.

Having the main Firefox and Chrome folders locked for security purposes does not seem to pose any major functionality issues for the majority of users, but having all Firefox Portable folders locked is unacceptable, since it affects Firefox Portable functionality and it creates severe issues with the file system.

The problem lies in the interaction of ESET and Firefox (and probably other browsers), thus there is absolutely no reason to make any adjustments to Windows, trying to install or uninstall specific updates.

Also, there is no point to try to change folder permissions, since the problem is not that you do not have the necessary permissions, but that the folders are being actively locked by the ESET services, which are still running even if you temporarily pause ESET protection or ESET firewall.

Last, but not least, you do not have to uninstall ESET, which in my opinion is an excellent antivirus program, you can leave it running as usual, and also leave enabled the generic ESET Browser Protection, which you can use for secure browsing.

ESET - Setup - Advanced Setup - Browser Protection - Safe Banking & Browsing - Enable Safe Banking & Browsing - Browser Protection - Secure All Browsers

Forums:

Firefox Portable

Can you please fix the 32-bit and 64-bit issues and options?

lwc — Wed, 24 Sep 2025 21:11:25 +0000

32-bit and 64-bit issues and options still states:

The 32-bit version of Firefox in the Firefox directory cannot currently be removed but will in a future release.

But is it still true since 2013's Platform 27.0, which states "This version introduces the option to leave off 32-bit app support in dual architecture apps" and even name checks Firefox?

In other words, the installation screen has "Include 32-bit Support" unchecked by default with the description "Allows the app to run on 32-bit Windows PCs".

BTW, there's still an empty FirefoxPortable\App\Firefox folder for some reason, could you maybe remove it?

Forums:

Firefox Portable

Can you please fix the license statement?

lwc — Wed, 24 Sep 2025 20:46:37 +0000

App License: Open Source (MPL/GPL/LGPL under Mozilla EULA)

- Mozilla Firefox, Portable Edition

While it was true originally, for the last 1.5 decades (since Firefox 13 in 2012) it has been strictly MPLv2.0.
There's a whole explanation about it in Wikipedia, with this source summarizing it:

The licencing on Firefox 13 has also changed. Now, rather than the old MPL 1.1 and disjunctive tri-licence, Firefox source and binaries are released under the Mozilla Public Licence 2.0.

The license's upgrade process was documented in Mozilla's wiki (starting with "We have a script which replaces existing tri-licence blocks with the MPL 2 boilerplate').

Please remember to likewise fix:

Firefox ESR (Extended Support Release)
Firefox Developer Edition
Firefox Beta
Firefox Nightly
Legacy versions (they may be legacy but every single version there is still much newer than v13)

Forums:

Firefox Portable

No way, for now, to get Firefox Portable Legacy 115.28.0 Italian

SwimmeRM+ — Sat, 20 Sep 2025 23:42:53 +0000

Hello John T. Haller,

just FYI and awareness few minutes ago, I found that there's no way, for now, to really get FirefoxPortableLegacy115_115.28.0_Italian.paf.exe because unfortunately, so far , same file is the only missing one from within its dedicated folder on SourceForge project involved server side area Mozilla Firefox, Portable Edition Legacy115 115.28.0 that only contains 38 files instead of the 39 of the preceding ...115.27.0... subfolder version.

P.S. I also hope I'm not doing wrong to report this to you from here, since I know no other forum Admin, and I've also assumed you may already very have good contacts, likely direct ones, with involved people maintaining SF project side, so I also hope, with your help , their next correction/solution might even be quickest possible one.

Many thanks in advance for your so kind attention and support, also from some other Italian people side that I'm quite sure will be very interested to get latest v115.28 release in our language ASAP too.
Best Regards

Rob

Forums:

Firefox Portable

Firefox Portable no longer starts.

rkumetz — Fri, 29 Aug 2025 19:46:08 +0000

I have been using Firefox Portable Version 142.0.1 for a while. Now it will not start.

The first thing I noticed was that my backup operation was having problems because it was saving information into the profile/datareporting/archive directory despite data reporting being turned off. Further complicating thing is that the archive directories and files require odd administrator access which foiled the backup and would not allow me to delete them.

Whether it is related or not, now it simply won't start up.

I copied a backup of the firefox portable directory to my desktop from a backup that was successful and that does start up.

Any clue what I need to do to get my Firefox portable back?

If I can get it back and stop it from saving those files that would be super terrific!

Thanks in advance.

Forums:

Firefox Portable

"FF portable appears to be running from a location that is read-only"

RogerL — Tue, 22 Jul 2025 10:16:54 +0000

This is incorrect. All my Papps are loaded on a USB microSD card which is working fine. I checked I can create a text file with Explorer in Firefox Portable's folder.

Any help appreciated,

Windows 11, version 24H2, FF portable 140.0.4

Forums:

Firefox Portable

Cannot open FF after stopping update

mozfan — Sat, 12 Jul 2025 23:41:26 +0000

As it has done before, FF started updating despite all settings against it. I interrupted it by pulling out the memory stick, but now it would not launch nagging about creating a new profile. I DO NOT WANT ANY UPDATES!!! They always carry unwanted changes forcing users to waste time restoring their settings if it's possible at all! We're aware of security risks - please respect our choices!

Sorry for the rant...What do i do now? I'm afraid to create a new profile as it might change something. How do I restore the current v.105 and stop updates once and for all? I love FF portable, no other browser comes close and I would hate to switch...
Thank you

ps this is the error message “Using an older version of Firefox can corrupt bookmarks and browsing history already saved to an exiting Firefox profile. To protect your information, create a new profile for this installation of Firefox.”

It looks like the profile is still there...

Forums:

Firefox Portable