Stuck on "Installing rootfs" when installing leJOS on the brick
I was able to fix the problem by creating a smaller partition on the SD card. (The idea came from this forum post; it was not necessary for me to buy a different SD card, despite what many people say there.) Using Windows 10, I was able to create a 4 GB partition with the “Computer Management” utility. After that, I used the ev3sdcard.bat utility again, and the installation completed successfully.

I do not know whether some intermediate value between 4 GB and 32 GB would also work. The forum posts I read suggest that 4 GB will be plenty of space.