File > Export Sprite Sheet exports with black background


When I export my animated sprite with Ctrl + E (or go to File > Export Sprite Sheet), it exports with a black background when it should be transparent. I’ve tried this with multiple versions of Aseprite, even on another PC, and with different sprites. They all show the same results.

This post is similar (Export Sprite Sheet -> Black background and outlines changed?) but there was no solution, and the problem is slightly different.