Sometimes the reminder does not appear until I reopen Thunderbird. I think I am noticing this more often when I snooze the reminder, I am not so sure about first instance of the reminder. My computer never sleeps. I do log into it with RDP every day. Sometimes Thunderbird crashes, but I don't know if that is related to this problem. I will try to determine if this is only happening with snooze, but if it happening with first instance of the reminder then that is a very big problem. User can't be missing important meetings and events. I am trying to reduce my reliance on Microsoft as much as possible, but it is very difficult and this problem will prevent me from using Thunderbird at work. Thanks for your help