@0xedd1e Hi I also looked at the release notes to see if something with Future/Concurrent was changed but nothing popped up. Worth trying going back to using earlier versions of QT? Well for test. it would be a good test if exact same code just works in say 5.6 and not in 5.10. But being stucked at 5.4 would be not so optimal. A note about the static. Just to be sure. the class that expects the Finished signal is a static member of some other class? As far as i can recall, you cant compile if you try to connect to a static class slot so im inclided to say that is not the issue. Since your mini sample works. There must be some difference in the real code. But i cant think of more to check.

@namit ok super.

@cxam Hahaha Solved, easily with "query.isActive". Sorry for the stupid question

Hi, Thanks for your response. The whole body of code is proprietary so I'm not sure I can share it in a public forum. However I can make a note that it used to work fine a month ago and after that no changes occurred to this code and no qt libraries were replaced, so the issue is like to be caused by hardware malfunction. Thanks again ))