Actually it was a gradual progression. At first, checking inbox or sent mail or archives, etc. was all fine, but messages were taking a few extra seconds to send, then getting stuck on "copy to sent folder"

Next, loading messages in the sent folder started to hang a long time

After that, loading messages everywhere took a long time, but still eventually loaded.

Now, nothing is working at all, the whole program is hanging right from startup and never completes at all. This all took about 3 hours from the start of the problem to now where the program has become totally useless.

A quick test - start *Windows'* safe mode with networking enabled - win10 https://support.microsoft.com/en-us/help/12376/windows-10-start-your-pc-in-safe-mode Still In Windows safe mode, start thunderbird in safe mode - https://support.mozilla.org/kb/safe-mode-thunderbird

Does problem go away? Please reply to let us know results.

Unfortunately when I start windows in safe mode with networking enabled, internet connection is lost and I can't find any way to fix this.

I tried simply running Thunderbird in safe mode alone, but this had no impact on the problem.

In that case, try some of the other items at https://wiki.mozilla.org/Thunderbird:Testing:Memory_Usage_Problems

Before spending half my life implementing items on that list, I'd like to try a simple fix and do a complete uninstall. I tried doing this but when I reinstalled it seems all my old data was retained. How do I do a full uninstall?

> do a complete uninstall. I tried doing this but when I reinstalled it seems all my old data was retained. Yes, of course, that is expected. Reinstalling any software should not lose your data.

> How do I do a full uninstall? If you mean, how do you start with an empty profile see https://support.mozilla.org/en-US/kb/using-multiple-profiles

And how do I do this when Thunderbird is frozen? These instructions appear to involve actions taken from within Thunderbird.