What is your operating system?
What is your Shotcut version (see Help > About Shotcut)? Is it 32-bit?
Can you repeat the problem? If so, what are the steps?
(Please be specific and use the names as seen in Shotcut, preferably English. Include a screenshot or screen recording if you can. Also, you can attach logs from either View > Application Log or right-click a job and choose View Log.)
It’s repeatable. I want to export one frame as png image. I enter export frame menu. Next instead of accepting default file name i put ex. blabla BUT WITHOUT any extension (I replace default file name). Png is selected as type of file. And then after clicking save, nothing saves. There is no any warning message. If I change the name from blabla to blabla.png then saving frame works ok. Definitely it’s some kind of problem with missing file extension. In my opinion in such a situation shotcut should either automatically add png extension (as png is selected as file type), either should display any error message. Just ignoring saving is the worst option here.