Title: Blank Screen after Activating CSS-Optimization Last modified: August 21, 2016 --- # Blank Screen after Activating CSS-Optimization * Resolved [pmcm](https://wordpress.org/support/users/pmcm/) * (@pmcm) * [12 years, 8 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/) * Hi, * i tried to install your plugin on my site [http://www.baby-cool.de](http://www.baby-cool.de) but if i try to activate css-optimization, i just see a white blank screen. Even if i try to active “just look in head” the error is the same. * html and js optimization are activated right now and work fine. but i don’t know why css doesn’t work. * PS: I’m also usin WP Super Cache with mod_rewrite. * [http://wordpress.org/plugins/autoptimize/](http://wordpress.org/plugins/autoptimize/) Viewing 10 replies - 1 through 10 (of 10 total) * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 8 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251225) * In some -rare, this is only the 2nd time I see this- cases [the new CSS optimizer](https://github.com/tubalmartin/YUI-CSS-compressor-PHP-port) backfires, leaving nothing but a blank page. In that case you can force Autoptimize to use the legacy CSS minifier by adding this to your wp-config.php: * ``` define("AUTOPTIMIZE_LEGACY_MINIFIERS","true"); ``` * hope this helps, frank * Thread Starter [pmcm](https://wordpress.org/support/users/pmcm/) * (@pmcm) * [12 years, 8 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251253) * That works! Thanks a lot!!! * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251384) * [@pmcm](https://wordpress.org/support/users/pmcm/); I’m working on 1.7.1 and would like Autoptimize to fail less … visible. Would you be willing make a small temporary change to autoptimizeStyles.php to see if that “fixes” the white screen? * Thread Starter [pmcm](https://wordpress.org/support/users/pmcm/) * (@pmcm) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251389) * [@futtta](https://wordpress.org/support/users/futtta/): Yes, no problem. What should i change? * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251390) * 2 changes actually; * 1. seeing if we get an error on the actual inclusion of the cssmin-library; 1. in wp-content/plugins/autoptimize/autoptimize.php on line 117 change 2. ``` @include(WP_PLUGIN_DIR.'/autoptimize/classes/external/php/yui-php-cssmin-2.4.8-1.php'); ``` 3. to 4. ``` include(WP_PLUGIN_DIR.'/autoptimize/classes/external/php/yui-php-cssmin-2.4.8-1.php'); ``` 5. in wp-config.php remove `define("AUTOPTIMIZE_LEGACY_MINIFIERS","true");` 6. empty autoptimize cache and see if you get an ugly error instead of a white screen 7. if so, revert the 2 above changes 8. if not, revert 1st change and continue to (2) * 2. if you still have a white screen (i.e. no ugly error), this change aims to have autoptimize fail more gracefully. 1. open wp-content/plugins/autoptimize/classes/autoptimizeStyles.php and on line 275 change 2. ``` //Minify if (class_exists('Minify_CSS_Compressor')) { // legacy $code = trim(Minify_CSS_Compressor::process($code)); } else if(class_exists('CSSmin')) { $cssmin = new CSSmin(); $code = trim($cssmin->run($code)); } ``` 3. into the safer 4. ``` //Minify try { if (class_exists('Minify_CSS_Compressor')) { // legacy $tmp_code = trim(Minify_CSS_Compressor::process($code)); } else if(class_exists('CSSmin')) { $cssmin = new CSSmin(); $tmp_code = trim($cssmin->run($code)); } } catch (Exception $e) { $CSSMinError = $e->getMessage(); $this->ao_logger("Could not minimize because: ".$CSSMinError); } if (!empty($tmp_code)) { $code=$tmp_code; unset($tmp_code); } ``` 5. with the AUTOPTIMIZE_LEGACY_MINIFIERS still removed from wp-config.php, empty the autoptimize cache and try if you get a white page now * After these tests you can revert all changes, off course! * thanks for your help! * frank * Thread Starter [pmcm](https://wordpress.org/support/users/pmcm/) * (@pmcm) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251391) * Hi, * if i do first changes, i get an “HTTP500: Internal Server Error”. * An if i do the second changes, i just get a blank screen without any error message. * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251392) * weird … an internal server error upon including the new cssmin-library? * could you try to change * ``` @include(WP_PLUGIN_DIR.'/autoptimize/classes/external/php/yui-php-cssmin-2.4.8-1.php'); ``` * in wp-content/plugins/autoptimize/autoptimize.php into * ``` try{ include(WP_PLUGIN_DIR.'/autoptimize/classes/external/php/yui-php-cssmin-2.4.8-1.php'); } catch (Exception $e) { $CSSMinError = $e->getMessage(); $this->ao_logger("Could not load minimizer: ".$CSSMinError); } ``` * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 7 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251397) * The internal server error is pretty weird, as it is caused by a simple inclusion of the cssmin-component (and not the minimization of CSS), so I’m thinking there might be a problem that is not purely related to the code here. * What system are you running your WordPress on? OS (Linux/ Windows/ …), webserver( Apache, IIS, ngix, ligthttpd, …), what version of PHP, what amount of memory available for PHP, …? * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 6 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251424) * I’ve just pushed a first test-version of 1.7.2 to the plugin repository with some extra checks before loading the minifiers, so it might fix the blank screen problem. You can [download the test-version here](http://downloads.wordpress.org/plugin/autoptimize.zip). Looking forward to your feedback! * Plugin Author [Frank Goossens](https://wordpress.org/support/users/futtta/) * (@futtta) * [12 years, 6 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251425) * and 1.7.2 is now live, fingers crossed the improvements in minifier-loading fix the blank screen problem. Viewing 10 replies - 1 through 10 (of 10 total) The topic ‘Blank Screen after Activating CSS-Optimization’ is closed to new replies. * ![](https://ps.w.org/autoptimize/assets/icon-256X256.png?rev=2211608) * [Autoptimize](https://wordpress.org/plugins/autoptimize/) * [Frequently Asked Questions](https://wordpress.org/plugins/autoptimize/#faq) * [Support Threads](https://wordpress.org/support/plugin/autoptimize/) * [Active Topics](https://wordpress.org/support/plugin/autoptimize/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/autoptimize/unresolved/) * [Reviews](https://wordpress.org/support/plugin/autoptimize/reviews/) * 10 replies * 2 participants * Last reply from: [Frank Goossens](https://wordpress.org/support/users/futtta/) * Last activity: [12 years, 6 months ago](https://wordpress.org/support/topic/blank-screen-after-activating-css-optimization/#post-4251425) * Status: resolved