Selected part of render rendered transparent

Hello!
I am having a problem with rendering selected parts of render. Full render was done fine, no problems, but when I want to re-render some selected parts it turning out like this?

When it render everything look fine until its done. Its just turning like that… How I can fix that?

Have you actually checked the output? In the render preview, this is normal- it will show you the progress briefly, then reset to transparent for the next frame

Actually no… where I can check output for that actually? And what to select/deselect to fix that issue?

Well, you’re rendering to a file somewhere on your computer, right? Have you looked at that file?

Oh yea I have something like this, but I there’s no saved files in that output anyway
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