HiFIrst of all im using WIN 10 so this applies to that OS, all i did was open my profile location and found 2 entrys one had a folder with a json file in it,the other profile folder had everything in it.i scrolled down the list to the entry labelled ...
I have used Thunderbird for so many yrs a true mozilla fan and a firefox one, but when supernova was installed i realised what a horrible interface it had, some would say "clean" but this is actually a step backwards it may be a re design but its lay...
