My Thunderbird recently updated itself to 128.2.0esr (32-bit). Right after that, my Gmail account in Thunderbird started a process of downloading messages into the Important Mail folder or All Mail and other folders. Thousands of them. It creeps along pausing occasionally, freezing my mail app, and can't do anything until it does whatever, then continues for a minute or two normally before freezing up again. It's possible most of the time to do something while it's downloading-- it halts then catches up and halts again in only a few seconds. Almost impossible to compose a message or read messages while it's downloading. Sometimes, if you click on something when it halts, it says "Thunderbird not responding" turns faded and crashes or have to go into task manager and end the process to get out of it. Right now, my mail is downloading with a total Important Mail quantity of (it reports now) 5787 messages. That quantity changes each time. I've left the mailer open just sitting there hoping it might finish whatever it needs to do, and then I can go about business without the freezing. But then it starts downloading mail again. Now it's switched over and doing it in All Mail-- 20,000 of those, and flipping between Sent Mail and then back to Important... The only workaround I've found is when it starts that activity, close the mailer and reopen it and then I have at least a few minutes to read or compose mail before it starts up and bollixes activity, and I have to close down and reopen to continue. I can find NO setting to adjust or turn this "feature" off. I have to go use the actual Gmail in a browser, which I hate, to get anything done. I've used Thunderbird since it first came out, even back to when it was Netscape mail before going independent as Mozilla and prefer to use it but can't with this downloading madness.