Highlight the account name in folder pane, right click, select 'subscribe' and UNtick the box for AllMail. That is the recommendation from Thunderbird. The Allmail folder doubles all retrieval and outgoing resource use and significantly increases disk space. After doing that, you should exit thunderbird and then delete the allmail folder in the profile to regain the space.

Provide more detail on why you cannot do this and we'll try to assist.

i tryed what you said but the folders come back i went in and uncheck the folder that did not help i just cant delete emails out of allmail folder ray n5iz

Do they come back immediately, or only after restarting thunderbird?