Have been using Firefox Portable (always updated to the latest version) at work for a number of years, due to being in a locked down admin-only environment running XP and IE6. Always worked fine and also used Firefox Sync to keep in sync with my normal (non-portable) Firefox at home.
They just recently added Firefox (non-portable) to the environment and it broke my portable. 50% of pages come up with the 'Untrusted .. Get me out of here .. Add exception' page. Usually repeatedly even when adding exception and returning to the page. A few sites (Facebook, PayPal) after adding exception come up stripped down to text and are unusable.
If I use this instance of FF portable at home, it works fine, no issues. Using the installed normal Firefox that work have installed, that works ok too (I cannot have both going however). I can't use works installed FF with my own sync as I have other intranet and internet pages I have to use, and obviously don't want any nsfw sites I don't notice in there.
Not sure how to troubleshoot this, even tried going back to pre-sync v3 version, then tried a few different versions from 4-9 which didn't fix.