INSTRUCTIONS ON HOW TO INSTALL IN WINDOWS BELOW

So far this is working fine with Windows 8.1 - I will report back if I have any issues in 7 or 10 when I get around to installing it on my other systems.

For those not understanding WHY this new setup is required, Firefox has completely changed how extensions will work moving forward. Long story short, they took away the deep functionality which pretty much all developers relied on. Trust me, no one is happy about it and the majority of devs are publicly jumping ship.

However, I'm not sure of the issue from reviewers about installing Python for this extension to work, since all it does is expand a few language extensions in the background on your computer. Python has been around since 1991 and trustworthy. A standard user will never see a difference in any normal day to day operations.

For those who do not understand how to install in Windows:
1. Install Python (Download from link, run file, and then follow install screens)
2. Download the linked .py file and then move it to a special folder or the root of your C:/ drive (I put mine under the python install folder/Lib)
3. Open a Windows Command prompt (Type command or cmd into Start Menu search and select the cmd.exe)
4. Navigate inside the command prompt to the folder where you put the file in #2 (i.e. "cd c:\path_of_file_folder")
5. Run the command given in instructions: "open_with_windows.py install" (You must be in the same folder as the file)
6. Click Test in the extension info screen inside of Firefox. It will tell you immediately if it worked and you can begin finding/adding external programs to launch

很好用自訂性很高
OS: arch linux

Thanks! Working perfect with my Ubuntu machine!

Works fine, lightweight open source .py helper file,* option to select all installed browsers, good job.

* with FF 57, all other "open with" addons require external helper files, too, one of them is 20 MB on Linux... However, the Python helper file has to be installed using the command line, which may be difficult for some users.

Have successfully transitioned to the new version with the external Python helper application (on ubuntu, a version of python was already previously installed). For the previous version, I had "browsers" (actually custom scripts) specified by command line, and the UI for the new version made it relatively painless to re-create them. The biggest frustration was that browsers configured under the old version aren't automatically imported into the new version upon upgrade - and in my first attempt to set a browser up, I got my entry for the "name" and the "command" field the wrong way round - but after correcting that mistake, it worked first time.

Пять звёзд за версию 6.8.6...
Вернулся на без проблемную версию 6.8.6, здесь хоть не надо устанавливать дополнительное "ПО"...
А разработчика я понимаю, не так легко подстроится под "Firefox 57", на который я вряд ли перейду, так как нужные мне приложения в нём не работают. А пока буду да последнего использовать "Firefox ESR 52".

Open With is a classic among add-ons. I use the add-on for web development and to open links in desktop software. The developer has been maintaining the add-on for years and has even released a modernized version as a WebExtension. WebExtensions must adhere to restrictions that the developer has overcome with a Python script. This method works fine on Linux.

Many thanks to Dark Trojan!

This is too complicated for me to get working. I need more info on the installation process.

PS. I use FF 56. Do I have to run 57 to get it working?

Edit: On +57 now and have looked more careful at installation process. Love it!