I've been using Thunderbird 60 with Win10 (on auto update) for some time without problems. So has my wife's computer. A few days ago, we both about simultaneously started having the same issues: When we check for new messages to download, the status bar says 'Searching' and nothing loads for 3-5 minutes; We're not able to send messages on any accounts; If we close and restart, we get a Thunderbird already running error. Safe mode is the same. All our email accounts are gmail.