I'm experiencing an unusable user interface. When I click around in the application nothing happens, after about 5-10 seconds i'm met with a "Not responding" title and a Windows "Not responding" popup dialog. If I just wait for a response it can take up to 5-20 seconds before the click is registered and executed. When switching applications using Alt + Tab the computer responds fast to every other program but when TB is selected nothing happens, until I wait 20 seconds, then the application appears. I searched around and investigated extensions, add-ons and plugins and found that McFee Anti-Spam and others could be the cause of trouble for TB. Regardless, all other programs responds to clicks in their UIs including McFee. With McFee Anti-Spam deactivated and other features striped I still had problems. I felt a better performance as 20 seconds became 16 seconds, but still the UI is unbearable. If I go to offline mode. The UI is fine. So the cause is the imap sync in the background. That tells me that background tasks of syncing and downloading content in the background as equal priority as the UI responsiveness. I can't understand why the two are not separated so the UI have priority and will respond regardless of the background activity. I have TB version 24.6.0 The lack of UI responsiveness make TB unusable. Properly separate the UI from the background tasks! When will those process be divided so that we can get a usable application? I expect TB to be able to handle at least 4-5 email accounts where 2 of those accounts hold at least a 1000-3000 messages. Regards, Steffen.