Pretty sure some/one of your history files are corrupt. You need to delete them and then it should start working again. Unfortunately you'll lose any history along with it. Files are found in; %appdata%\maxthon3\UserData\Users\[guest or email address]\History If you do do this make sure you keep a back up of your data! You may not have to delete them all, some trial and error delete/test and see if it starts working properly. If it doesn't then try another history file.