Quote Originally Posted by .paul. View Post
It is a threading problem. You're overloading the UI thread. As Shaggy Hiker told you, the code you tried to move to secondary threads was unsuitable for moving to secondary threads, as it interacted heavily with UI elements (controls).
What should I do then to carry out the task? With or without threads I have the bug. I've never had this sort of issue before so I don't know what I should do to get the code working now...