Excerpt textarea missing on post editing page in admin panel

Question

Why is that? It's a new installation.

EDIT: I don't have plugins installed and I tried to restore default theme to Twenty Ten, but it didn't change anything.

Answer 1

Upper right corner in posts editing page > "Screen Options"...there you have to check "Excerpt" ;)

Answer 2

If you already tried to add it at Screen Options in Upper Right Corner (in older versions)... try it:

Add the following code to your theme’s functions.php file or a site-specific plugin:

add_post_type_support( 'page', 'excerpt' );