Reply To: Why does my uv unwrapps turn green when “packing” the islands?

@arev like Kent already said: part of your mesh is hidden.

Select all, go into Edit Mode and select all:

now press ALT+H:

Sync Selection and select only the ‘new’ part in the UV Editor:

You can see you’ve got some ‘double’ geometry; delete that and repeat that because there is another one just like that.

Then three of the bottom planks have no seams and therefor use the default Cube UV’s:

Fix that and your UV’S should be pretty blue.