no puedo actualizar a WP 4.6.1

Estimados

He tratado varios dias de actualizar a WordPress 4.6.1–es_ES , pero es inutil.
He desinstalado todos los plugins y a pesar de ello, sigo igual.
En todos los casos me aparece el siguiente error

‘Descargando paquete de instalación desde https://downloads.wordpress.org/release/es_ES/wordpress-4.6.1.zip…

Descomprimiendo actualización…

Verificando los archivos descomprimidos…

Preparando para instalar la última versión…

No ha sido posible instalar la actualización debido a que no se han podido copiar algunos archivos. Normalmente esto es debido a permisos de archivo inconsistentes.: wp-admin/includes/options.php, wp-admin/includes/class-walker-nav-menu-edit.php, wp-admin/includes/class-wp-screen.php, wp-admin/includes/credits.php, wp-admin/includes/network.php, wp-admin/includes/edit-tag-messages.php, wp-includes/class-walker-comment.php, wp-includes/class-wp-rewrite.php, wp-includes/customize/class-wp-customize-nav-menus-panel.php, wp-includes/customize/class-wp-customize-nav-menu-section.php, wp-includes/customize/class-wp-customize-header-image-control.php, wp-includes/customize/class-wp-customize-image-control.php, wp-includes/customize/class-wp-customize-nav-menu-item-control.php, wp-includes/customize/class-wp-customize-nav-menu-auto-add-control.php, wp-includes/customize/class-wp-customize-nav-menu-setting.php, wp-includes/customize/class-wp-customize-site-icon-control.php, wp-includes/customize/class-wp-customize-media-control.php, wp-includes/customize/class-wp-customize-nav-menu-control.php, wp-includes/customize/class-wp-customize-nav-menu-item-setting.php, wp-includes/customize/class-wp-customize-filter-setting.php, wp-includes/customize/class-wp-customize-nav-menu-location-control.php, wp-includes/class-wp-roles.php, wp-includes/class-walker-category-dropdown.php, wp-includes/class-wp-comment.php, wp-includes/class-wp-tax-query.php, wp-includes/embed-template.php, wp-includes/class-wp-widget.php, wp-includes/class-wp-user-query.php, wp-includes/rest-api/class-wp-rest-request.php, wp-includes/rest-api/class-wp-rest-response.php, wp-includes/rest-api/class-wp-rest-server.php, wp-includes/widgets/class-wp-widget-tag-cloud.php, wp-includes/widgets/class-wp-widget-recent-comments.php, wp-includes/widgets/class-wp-widget-meta.php, wp-includes/widgets/class-wp-nav-menu-widget.php, wp-includes/widgets/class-wp-widget-search.php, wp-includes/widgets/class-wp-widget-categories.php, wp-includes/widgets/class-wp-widget-links.php, wp-includes/widgets/class-wp-widget-rss.php, wp-includes/widgets/class-wp-widget-calendar.php, wp-includes/widgets/class-wp-widget-pages.php, wp-includes/widgets/class-wp-widget-archives.php, wp-includes/widgets/class-wp-widget-recent-posts.php, wp-includes/widgets/class-wp-widget-text.php, wp-includes/class-wp-comment-query.php, wp-includes/class-wp-widget-factory.php, wp-includes/class-wp-http-cookie.php, wp-includes/js/wp-embed-template.min.js, wp-includes/js/wp-embed.min.js, wp-includes/js/wp-embed-template.js, wp-includes/js/wp-embed.js, wp-includes/class-wp-http-streams.php, wp-includes/embed.php, wp-includes/class-walker-page-dropdown.php, wp-includes/class-wp-http-proxy.php, wp-includes/class-wp-meta-query.php, wp-includes/rest-api.php, wp-includes/class-walker-category.php, wp-includes/class-wp-http-curl.php, wp-includes/class-wp-http-encoding.php, wp-includes/class-wp-network.php, wp-includes/class-wp-role.php, wp-includes/class-wp-term.php, wp-includes/class-wp-user.php, wp-includes/class-walker-page.php, wp-includes/class-wp-oembed-controller.php, wp-includes/random_compat/random_int.php, wp-includes/random_compat/random_bytes_libsodium.php, wp-includes/random_compat/byte_safe_strings.php, wp-includes/random_compat/random_bytes_com_dotnet.php, wp-includes/random_compat/random.php, wp-includes/random_compat/random_bytes_mcrypt.php, wp-includes/random_compat/random_bytes_dev_urandom.php, wp-includes/random_compat/random_bytes_openssl.php, wp-includes/random_compat/cast_to_int.php, wp-includes/css/wp-embed-template.min.css, wp-includes/css/wp-embed-template.css

Instalación fallida’

Que podra ser?
Gracias de antemano por sus aportes