suite aux probleme de fonctionnement et suivant une methode citez ailleur dans les commentaire mais sous windowNoté (par Zein Adi, il y a un an):
sous linux :
dans .config/firefoxprofileswitcher/ ajouter un fichier config.json inserer "browser_binary": "/usr/bin/firefox"} sauvegarder .
relancer fx

This is a fantastic add-on that really helps me use Firefox in the multiple ways I need to without having to log in and sync multiple Mozilla profiles, however, it's currently malfunctioning (23-Mar-2024). Thanks to olivrrstray's review I was able to get back in and I concur with JavitoPlay, the dev is most likely working to update it.

Now its broken the "click" on the profiles, but you can go to edit profiles, and "set as default" to open the profiles you had keep.

I suppose the developer is working to fix it

In general, this extension its great.

Broken with the March 19th update, 124.0.

Edit:
For the more tech savvy, there is a workaround on Issues tab on the Github page.

For the less tech savvy who have Windows:
1. Hit Windows + R.

2. Put "%APPDATA%\nulldev\FirefoxProfileSwitcher\config\" in the prompt, and hit "ok." This will open the folder with configuration files.

3. Copy the path; this is the address in the top bar. It should look similar to this:
C:\Users\[yourusername]\AppData\Roaming\nulldev\FirefoxProfileSwitcher\config

4. Open the notepad app, create a new file. Paste the following text in the notepad:
{"browser_binary": "C:\\Program Files\\Mozilla Firefox\\firefox.exe"}

5. Open the File menu, click Save As.

6. In the address bar, paste the address you saw before, and change "Save as type" from Text documents to all files. You should see files like "avatar.json"

7. Save the file as: config.json

8. Reopen Firefox

Was working well but now unresponsive, cannot access my other profile.

Update - fixed it thanks to olivrrstray's short guide.

It worked fine until Firefox version 124. Now it doesn't react on when I want to switch profile.

Works well but requires some initial setup and basic knowledge of how Firefox profiles work. It would be nice if this extension allowed users to upload their own profile picture and/or offered the option of using each Firefox account's avatar as the profile picture.

Very good addon, simple and straightforward. Only 4 stars because I couldn't figure out a way to pick my own profile picture, which would make it perfect IMO. Should be a native part of Firefox.

This is a functional add on its good enough that it should be a default part of firefox. I deducted a star because I would like to be able to choose my own profile pictures instead of the ones presupplied. (Maybe this is possible by finding a directory somewhere but this shouldnt have to be difficult)

Great extensions, exactically what I wanted. It would be great to be able to use custom photos for those profiles though. Hope that comes out soon.

It's really useful for me as I have two different Etsy stores and this is the easiest way to be logged into both rather than having to log out and in all the time. Among other purposes. The main issue I have is that I would really like to be able to use my own images for the icons and there doesn't seem to be a way to do that. It's a minor issue but as someone who likes to customise everything to the hilt it's just one of those things that bothers me whenever I switch profiles.

It's a pretty cool extension, I believe the only one of its kind. I would give it a 5 star rating if it changed the icon of the program when you do alt-tab to add your profile's icon like it happens in chrome. Thank you!

I am pleased with this add-on. As noted by a previous reviewer, I would like to have the ability to password protect the different profiles.

Works, but is quite difficult to set up on mac os.

This is amazing. It is the main feature that I have been wanting in Firefox for ages. It is only missing 2 things, adding the first one will improve my review to 5 stars. Please have this add-on change the icons on the taskbar or dock to match the profile icons so we can quickly tell which Firefox window is which profile when the windows are hidden behind other windows. Also, please add keyboard shortcuts for switching profiles. Great work, I love what you have done with this already.