This is an issue that cropped up with the last update to T-bird. It retrieves and displays emails as well as it always has, but now when composing an email reply, T-bird completely locks up, can't shut it down by any means other than using Task Manager and killing the process. Before killing it, though I expanded T-bird's processes, and it listed five instances, one of which read "Not responding." When this happens, the cooling fan in the laptop kicks into high gear, until shortly after I kill T-bird. Needless to say, this is intensely annoying and inconvenient. I belong to an extremely busy recovery group, and email is my primary contact with them, so this makes things a royal pain. I've had to resort to hitting "Respond" to open a new email, then firing up the text editor to compose the reply, then cut/paste that in and send it. Workable, but really... it *was* working fine, and now it isn't, and I haven't changed a thing, Windows hasn't updated, no new apps or anything... it just stopped working. I've tried a number of suggested fixes, such as removing all add-ons (removed, not disabled) and themes, creating a new account (which worked okay for about a week, then it too started locking up). About the only thing I haven't tried yet is uninstalling T-bird and re-installing it, which I'll do if I absolutely have to, but I'd rather not go through the hassle of rebuilding everything if there's any other way to fix this. Is there any kind of information or file/s I can provide that someone may be able to make some sense of? I'd REALLY appreciate it. I've used T-bird since I had internet access (back when Alta Vista was still a thing), and I love it - - no other email app offers the breadth of features that T-bird does, even paid apps. I'd truly HATE to have to switch to something else over this!!