When I start the shotcut, a white window appears

[shotcut]

This is a sign of incompatibiltiy with the OpenGL and DirectX on your system. You can try the registry files in the thread below to workaround. Otherwise, it cannot be fixed.

Video Mode

Introduction Video Mode is the project resolution, aspect ratio, frame rate, and color space. It is important to set this as you desire at the beginning of your project. If you try to change it later Shotcut will try to retain the timing of edits, but some users have reported problems, and it is risky. Also, at this time Shotcut will not automatically adjust anything for you related to size and positioning of elements like text and picture-in-picture when changing resolution. You can think of…