Recently, I had to move a personal settings of Firefox in Microsoft Windows XP machine to Windows 7. As a reminder for myself, I write down the instruction here: Copy a folder C:\Documents and Settings\ userid \Application Data\Mozilla\Firefox in XP machine to C:\Users\ userid \AppData\Roaming\Mozilla\Firefox in Win7 machine. Copy a folder C:\Documents and Settings\ userid \Local Settings\Application Data\Mozilla\Firefox in XP machine to C:\Users\ userid \AppData\Local\Mozilla\Firefox Note that the above ' userid ' is an account name of the user. A similar copying policy is applicable to Mozilla Thunderbird.