No you need to disable whatever software is making Thunderbird non functional. Given the device is a Dell and they traditionally provide McAfee with their product preinstalled my guess is it will be that long term mail dysfunction causer that is the root of your issue All those folders you see in Thunderbird are caused by file contention and that is usually the antivirus locking up files when Thunderbird is trying to use them. You can start by deleting all of them. All this inbox folder all the nstmp folders and all of the compact backup folders.