Hello

what is the meaning of your post title 'Thunderbird mil' ? I can't fathom it. About your problem, it's clearly not a software problem, as Thunderbird is supposed - like all software - to have some part of the system it is able to write to. If it can't, it maybe that there is not enough disk space, that is, your disk is full, or that there is a hardware fault on your disk, or that somehow you ran your software sometimes as administrator, and now as a simple user and as a follow-up Thunderbird has not the necessary rights. In all of these cases, it's a generic computer problem, that can best be solved by a generic computer help.