Also look in the folder into which you 'installed' FirefoxPortable and then open the folder "Other" then open the folder "Source". In that Source folder you will see a file titled "Readme.txt" there are notes and instructions in there that say how to run FirefoxPortable at the same time that your fully installed Firefox is running.
Use Portable Apps on both Flash Drive and HDD/SSD.
http://www.webmechs.com/web-development-tutorials/multiple-firefox-porta...
And step-by-step instructions here too:
https://lifehacker.com/5062410/customize-your-own-portable-firefox-six-pack
Also look in the folder into which you 'installed' FirefoxPortable and then open the folder "Other" then open the folder "Source". In that Source folder you will see a file titled "Readme.txt" there are notes and instructions in there that say how to run FirefoxPortable at the same time that your fully installed Firefox is running.
Use Portable Apps on both Flash Drive and HDD/SSD.