Hi. When I open "Sprite Packer" window I see info "Legacy sprite packer is disabled. Enable it in Edit>Project Settings>Editor". So I open this settings, but there "Sprite Packer > Mode" is set to "Always Enabled". But in Sprite Packer window I still have previous info and I can't use it. So why I can't use it, and how to turn it on? Thank you.
"Always Enabled" is for the new sprite atlases. If you really are using the old system, then you should use the "Legacy Sprite Packer" options. (That is, one of the first options in the "Sprite Packer" menu.
What do you mean "old system"? I'm using Unity 2017.3. And you are correct, when I set to legacy then I could use "Sprite Packer". So why I can't use "Always enabled"? But how can I link images from sprite atlas to my game objects like on this video: I don't have this buttons. Thank you.
The Sprite Packer is the "old" way of making spritesheets, whereas the Sprite Atlas is the new one. If you haven't got an old project that uses the Sprite Packer, then look into the Sprite Atlas instead. BTW: My menu looks like this:
The 2017 Generate Atlas is creating non square POT atlas - how do you force it create a square POT atlas?