I am using FirefoxPortable v88. This works perfectly under Windows 7 but when the same flash drive is started using Windows 10 64-bit I receive the following message:
"You've launched an older version of Firefox
Using an older version of Firefox can corrupt bookmarks and browsing history already saved to an existing Firefox profile. To protect your information, create a new profile for this installation of Firefox.
[Exit] [Create New Profile]
Of course creating a new profile means loosing not only bookmarks and browsing history, but apparently all add-ons and themes as well. At least some of the files associated with the previously-installed add-ons appear to have been deleted from the \PortableApps\FirefoxPortable\Data\Profile folder.
FirefoxPortable then creates a directory structure containing hundreds of files in:
If a regular non-portable version of Firefox is already installed on the host computer, of course it will have already created the folders above; and in that case FirefoxPortable seems to use those folders.
Going to about:profiles and attempting to [Set as Default Profile] and [Restart] simply goes back to the warning above and requires creating yet another profile.
So FirefoxPortable is no longer really portable under Windows 10?
about:profiles does not support command line switches or portable mode and should not be used. As long as you are properly running FirefoxPortable.exe directly or via the PA.c Platform, it runs fine on Windows 7, 8, and 10. The profile is not stored locally but some files do need to be created temporarily on the local C drive.
Is your drive's permissions set correctly to allow use on all machines either by using a simple format like exFAT/FAT32 or an NTFS format with EVERYONE allowed FULL CONTROL?
Sometimes, the impossible can become possible, if you're awesome!