Eek. Didn't you want those messages?

Of course, Thunderbird downloads them. They are on your server and Thunderbird doesn't know that you have already read them.

What's puzzling me is that if you wanted to keep the messages (why else are they still on the server?) why are you now deleting them?

I'd go to the hotmail website and consider which messages I want and don't want. I'd put all the ones I want to keep, but not see in Thunderbird, into a separate folder, and not subscribe to that folder in Thunderbird.

Or did you leave them all in the account's Inbox? Is it a POP-connected account? If so, please stop deleting, NOW because they may well be your only copy of those messages.

Gmail has a handy "recent" setting for situations like this. where it downloads to a client only those messages below a certain age. I don't know if hotmail has anything similar.

Umb, no, if I wanted those messages I probably wouldn't be asking how not to download them (all 35 million of them,each time I install a mail client). These are almost entirely garbage messages that are just cluttering up my inbox and using data downloading, and, mostly, wasting my time every time I have I install a mail platform on a device and have to deal with this (if I really wanted to keep the message, I'd protect it). This morning, I selected thousands of messages,without regard for their content, and just clicked "del"; Now, at the bottom of the screen TB is showing "Downloading 1 of 22456", and I constantly have the rotating circle thing (in Windows speak, this program is doing something). I cannot figure out how to get messages off the Hotmail server, the other potential solution would be a setting in the mail program to only go back a few months, or whatever you set it at (some messages are like 25yrs old - I really don't need most of those, actually).

Do you really need to keep this account? It sounds as if it has become useless to you, so why do you keep reinstalling it?

You can't afford to neglect a working account. Only you can decide what is and isn't junk or spam and so you need to make those decisions. Junk Controls and spam detectors can help, but they make mistakes and need to be watched over.

I think you have to be patient, install the account, delete batches of messages. Do it once and it never has to be done again. And keep the spam/junk down by dealing with it on a little and often basis. And all of this is probably more easily done in Thunderbird than in the web browser. They tend to be structured to work page by page, limiting you to working with 10 or so messages at a time.

The ideal would be to go to the root and delete or clear the folders there. But Hotmail won't give you such access to their servers.