Index: wp-admin/includes/plugin.php
===================================================================
--- wp-admin/includes/plugin.php	(revision 7840)
+++ wp-admin/includes/plugin.php	(working copy)
@@ -175,27 +175,34 @@
 		update_option('active_plugins', array());
 		return;
 	}
+	
+	//Invalid is any plugins which are deactivated due to error.
+	$invalid = array();
 
 	// If a plugin file does not exist, remove it from the list of active
 	// plugins.
 	foreach ( $check_plugins as $check_plugin ) {
-		if ( !file_exists(ABSPATH . PLUGINDIR . '/' . $check_plugin) ) {
-			$current = get_option('active_plugins');
-			$key = array_search($check_plugin, $current);
-			if ( false !== $key && NULL !== $key ) {
-				unset($current[$key]);
-				update_option('active_plugins', $current);
-			}
+		$result = validate_plugin($check_plugin);
+		if ( is_wp_error( $result ) ) {
+			$invalid[ $check_plugin ] = $result;
+			deactivate_plugins( $check_plugin, true);
 		}
 	}
+
+	return $invalid;
 }
 
 function validate_plugin($plugin) {
 	if ( validate_file($plugin) )
 		return new WP_Error('plugin_invalid', __('Invalid plugin.'));
+
 	if ( ! file_exists(ABSPATH . PLUGINDIR . '/' . $plugin) )
 		return new WP_Error('plugin_not_found', __('Plugin file does not exist.'));
 
+	$plugins = get_plugins();
+	if ( ! isset($plugins[ $plugin ]) )
+		return new WP_Error('plugin_not_proper', __('Invalid plugin.'));
+
 	return 0;
 }
 
Index: wp-admin/plugins.php
===================================================================
--- wp-admin/plugins.php	(revision 7840)
+++ wp-admin/plugins.php	(working copy)
@@ -39,7 +39,10 @@
 $title = __('Manage Plugins');
 require_once('admin-header.php');
 
-validate_active_plugins();
+$invalid = validate_active_plugins();
+if( ! empty($invalid) )
+	foreach($invalid as $plugin_file => $error)
+		echo '<div id="message" class="updated fade"><p>' . sprintf(__('The plugin <code>%s</code> has been <strong>deactivated</strong> due to <em>"%s"</em>.'), $plugin_file, $error->get_error_message()) . '</p></div>'
 
 ?>