I have made no changes to my Thunderbird account settings and am know receiving error MBR1212. I am no longer able to log in to my email account through Thunderbird. The only change to my system is the recent upgrade to Windows 10 (done today). I have followed the instructions found in troubleshooting by deleting all previously saved passwords to no avail. I have researched both the internet at large and the Mozilla support forums for a solution only to find none. Please advise.