If you are running Windows, please, as a diagnostic, start the Operating System in Safe Mode with Networking privileges and see if the problem persists. If the problem is resolved, there is likely to be a conflict between TB and another piece of software. By launching background software one by one, it should be seen what the conflict is with. Most of these issues seem to be associated with Third Party anti-virus software so turning that on first if you use it would be the way to go.