Using Windows 10 (latest upgrade) on PC, with Kaspersky Total Security: in the past 2-3 weeks, whenever I open T'bird or go into the program, the system freezes and I get a "Thunderbird not responding" message...it takes between 15-20 seconds for any incoming message I click to appear. I have tried everything: restarting T'bird, restarting the computer, uninstalling ALL add-ons, running CCleaner, deleting Chrome and all its extensions (which I read can cause problems), not allowing Kaspersky to scan incoming emails...but nothing makes any difference. This is the first time I've ever experienced this with T'bird after using it for years. I have 4 separate IMAP accounts through Gmail, which I've also had for years.