I've had some problems on a couple of my systems running Portable FF, in which profiles apparently got corrupted. The major symptoms included incomplete display of page elements on certain web pages, limited or selective functioning of Javascript (worked on some websites, though not on others), inability to sign in to webmail-based email accounts. Trying to troubleshoot this proved tedious and not very productive. As a temporary workaround, I used this
https://addons.mozilla.org/en-US/firefox/addon/profilistportable/?src=api
to make a fresh, minimal-extensions profile I could switch to, so as to regain the lost functionality. This got the job done pretty well, but it was a bit cumbersome and clearly a workaround. Perhaps having some of the extensions is problematic, but they add too much value for me, so I'm unwilling to give them up.
I had also either previously bookmarked or recently taken another look at these:
https://portableapps.com/node/5376
https://portableapps.com/support/firefox_portable#second_profile
What I may end up doing is to standardize on a good, working profile from another computer, which has pretty much everything that I wanted in it. That will mean transferring it to the other computers, replacing the corrupted profiles with it, and starting a regimen of backing *it* up against possible future corruption. (By now, I've gotten to using Portable FF exclusively, rather than the installed version. It has been my experience that allowing Portable FF to update automatically can lead to disaster, so I always do that manually.)
Anyway, I just came across this
https://developer.mozilla.org/en-US/docs/Profile_Manager
which looks quite promising on paper, incorporating a lot of Profile control under one roof. It does not mention the portable version, but I suspect that it won't apply to Portable FF. Could it be that profile management and Portable FF just don't mix very well ?
The profile manager in Firefox itself works with local profiles only.
The only reason you'd have this many corrupt profiles is either hardware issues with the drive or USB ports themselves, failure to properly close Firefox (unsafe eject, shutting down Windows while Firefox is running which can crash it), or a severely misbehaving extension or combination of extensions that don't play together nicely. I personally haven't seen a corrupt Firefox profile on any of my Firefox installs in many years.
Sometimes, the impossible can become possible, if you're awesome!
I can't rule out misbehaving extensions, or combinations of them, but I note a tendency of portable FF itself to crash (saying that it needs to be restarted) a bit more often than I would have considered to be normal. This I thought had something possibly to do with dialing up certain web pages. The "almost no extensions" profile was not immune to it. I have not been using installed FF, and so can't compare to that. There are usually 6 - 8 tabs open, though.