Thunderbird not responding, probably connected to tasks

I've started using the task function a couple of months ago. So far no issues, I sometimes put a check on the finished tasks and then they disappear. Only yesterday, suddenly all the completed tasks reappeared and I couldn't check them anymore. Since today, Thunderbird has stopped responding entirely. I open the program, and it immediately crashes. I cannot do anything inside the program, because it does not respond. I cannot delete tasks. I cannot empty the cache. I cannot disable anyhting. I have tried reinstalling, but it remembers my login data and the problem persists. I have tried restarting the computer, to no avail. If I could I would simply delete all tasks (I have one on daily repeat that I assume is the culprit), but I cannot do that, since Thunderbird stops responding the moment I start it up. Please help.