Ultimate Translate only setted on: Translations have been disabled for all posts and pages.

I've installed UT like described on instructions via FTP on mu-plugins, but plugin seems not visible; then I've tried to install it via zip upload from WP, and it was installed in panel; then I've set it to install on whole site. First: however, plugin seems installed in plugin directory, not in mu-plugin; however, in pages, there is always the same setup: "Translations have been disabled for all posts and pages."