Platform 15.0.2 (May 17, 2018). Please donate.
400+ real apps, New: Falkon browser (Jun 04, 2018)
Over 980 million app downloads
How could one open 2 Firefoxes at the same time?
This message appears when trying it (saying, another instance is already running):
If you check out the help.html within Firefox Portable, it links to the readme.txt that has advanced options for the launcher. Among those is AllowMultipleInstances in the FirefoxPortable.ini file once you copy it next to FirefoxPortable.exe. Note that this will leave things behind and break the ability to do file associations or launch either version a second time.
Sometimes, the impossible can become possible, if you're awesome!
Thank you very much! Have it working now.
Windows 10 Home, 64bit