@
jation - I've seen posts here referring to corrupt/missing fonts causing problems, I don't understand details - you could try going back to the default system fonts
Maybe someone can jump and give advise on that issue.
I really did mean firefox - on my rig firefox is a much slower to start than calibre is (because I have too many extensions that 'I can't live with out'

) - I was wondering if firefox was OK on your rig
Let us know how the 32bit version goes ?
BR