Dragging second video only imports audio

Hello,
Since I use version 17, when I drag(import) a second clip to the timeline only imports the audio and not the video.
I have always to createa new timeline, copy everything I had and only a that moment the importation works.
I upgraded it 2 times but the problem still continues
Actually I'm using Davinci Resolve 17.2.2 build 4 (the last one) on Windows 10.
Since I use version 17, when I drag(import) a second clip to the timeline only imports the audio and not the video.
I have always to createa new timeline, copy everything I had and only a that moment the importation works.
I upgraded it 2 times but the problem still continues
Actually I'm using Davinci Resolve 17.2.2 build 4 (the last one) on Windows 10.