For the last few weeks (ever since one of the all-to-frequent Firefox crashes that I experience) I’ve been unable to use the WordPress visual editor to write my posts.  If I switched to another machine then everything was fine – the problem only existed in Firefox on one machine.  After seeking help on the WordPress support forums, someone tactfully suggested that I ask for help on the Mozilla forums… I wasn’t hopeful (as this problem seemed to be specific to WordPress); however the advice I was given was spot-on – it turns out that my issue was a corrupted Firefox profile.

After creating a new profile and copying key settings from my old profile (I copied bookmarks.html, certs8.db, cookies.txt, formhistory.dat, history.dat, hostperm.1, key3.db, mimeTypes.rdf and signons2.txt), I was able to relaunch Firefox and everything was back to the way it should be, complete with browser history, bookmarks, cookies, stored password, etc.  It should also be possible to copy items such as user preferences, search plugins and extensions but that’s not recommended if there were problems with the previous profile, so I reinstalled the couple of Firefox add-ons that I do use (the British English Dictionary and Web Developer extensions).