Windows 10 Pro x64, 8Gb RAM Periodically, and without warning, Thunderbird (v52.1.1) will go into a 'not responding' state for up to a minute, whatever activity is under way. Windows 10 Task Manager shows 'thunderbird.exe' is not responding because the process is in a wait chain for internet activity - "One or more threads of thunderbird.exe are waiting to finish network IO" - sometimes with more than one element, quoting a thread number. As far as i can see, the only way to resolve this, apart from waiting for it to resolve itself, is to terminate the process - not helpful. Eventually the process responds again, and carries on where it left off - immediately or shortly after, the wait chain disappears. Is there anything that can be done in the app or in Windows 10, to avoid these interruptions?