Ubuntu upgrade from 16.04 to 18.04 is taking too long

I got the same message. Pressing Enter got it going. Not sure what the message means, but pressing Enter did the upgrade from there.

I just had the same. How I fixed it:

1. cp /etc/apt/source.list.distUpgrade
2. apt update
3. sudo do-release-upgrade

It then should start installing again. Do not press Ctrl+C, but just hit [ENTER]