Showing PHP And SQL Errors And Debugging a Blank White Page In Prestashop

May 14, 2013794Sergei Guk

We all make mistakes while developing and need to know where is the error occurred, but Prestashop will show the blank/white screen in case of any issues.

To activate a debug mode for Prestashop versions < 1.5.3 you need to open config/ and find the following lines:

Then change ‘off’ to ‘on’ and false to true, like this:

Besides, if you have the 500 error page you need to edit config/ and define _PS_MODE_DEV_ to true as will be described below.

In Prestashop 1.5.3+ you need to edit config/ Find the following line

and change it to

What this will do? There is an ‘if’ loop below this line

As you can see, if _PS_MODE_DEV_ constant is defined, Prestashop will display not only PHP and SQL errors but also compatibility warnings.

I believe this will probably be enough for you to resolve a blank white page. Remember to turn debugging off when putting your store to live or after you fixed your errors.


  1. Also don’t forget to set error_reporting(E_ALL); in your config/

  2. can not found

    /* Debug only */
    @ini_set(‘display_errors’, ‘off’);
    define(‘_PS_DEBUG_SQL_’, false);

    in in config folder

  3. What is your Prestashop version? If it’s 1.5.3 and later (as it’s written in the article) you need to edit in config folder ONLY

    /* Debug only */
    define(‘_PS_MODE_DEV_’, false);

    and change it to

    /* Debug only */
    define(‘_PS_MODE_DEV_’, true);

  4. Hello Sergei,
    I run PS v1.5.4.1
    And have turned the things on, for php error reporting.
    But I have the follow prob, when I in the BO, click on the tab Advance parameters, Configuration information, I receive a blank, white page, and when I turn dev tools on, on Chrome, the follow message can I see,

    Request Method:GET
    Status Code:503 Service Unavailable
    Request Headersview source
    Cookie:jirafe.metric.boxes=%7B%22revenue%22%3A%7B%7D%2C%22orders%22%3A%7B%7D%2C%22visits%22%3A%7B%7D%2C%22conv_rate%22%3A%7B%7D%2C%22aov%22%3A%7B%7D%2C%22rpv%22%3A%7B%7D%7D;; cookie_ue=1; ffdbd13d96d903c026c4876e97eb63a4=22hq01YtzSw%3DnJc1UVrJBZs%3Ds1R%2F%2FVTI8ok%3D7G5eLCXwBi0%3DFNXio%2BHVa%2Fw%3DWKfUm8UQITo%3DGL8FikPgbNE%3DeXA7gMVHM%2B4%3DO2PS22CZQ9I%3DkzX3DRsKB7Y%3DjNbhNcJXmW8%3D7xqWfoMgcN0%3Dv%2FSEcDgtUbY%3DZbi5bx79XiQ%3DDh2xOv8j5jg%3DgBXHGAq8L%2BE%3Dr4tCYsoDURo%3DK700IJSo1x0%3D000137; 44c621219e3f66a7d4725c437c8fb0f8=22hq01YtzSw%3DnJc1UVrJBZs%3DoOerxDIQ3iE%3DkZSJARK4hlM%3DFNXio%2BHVa%2Fw%3D4GSbjdlMn%2F8%3DKl0sZH9rT1M%3DsXtwVum1VJw%3DRrDntAqQnug%3Dlc%2BnYrTebmM%3DFVjNbJd4Esg%3D3s1qvjGC5lA%3DpxZHfpVJXtY%3D8yj4%2BAhPTy0%3DTmHTd1Qa%2F58%3Dl8oSeFgYZYU%3D%2F7Wk2H7CqnM%3D5%2Fk73gytZ4A%3DRKCKwDXu38Q%3Dp6e6KOoJwQI%3Di5wuYCBYZgw%3DvnIHwTdcqo4%3DKLKlbrISFk4%3DUw%2FoCXVEMhE%3D7Od%2BDTAr4bA%3DWKfUm8UQITo%3DGL8FikPgbNE%3DcDwUB8t10o0%3D1D0ub9BBRYE%3DGYRNGzxlN64%3DeRS%2B8HqFDFY%3Dz2446%2Ftt1xk%3DyksKdMSA6Ik%3Dn0rJCLVhbpI%3DnOGSxnbkbCQ%3D000276; __utma=20860524.1918701170.1370792655.1371236143.1371241892.37; __utmb=20860524.16.9.1371242239421; __utmc=20860524; __utmz=20860524.1370792655.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); _pk_id.129520.38c3=062b112c89085df4.1370792656.37.1371243733.1371236176.; _pk_ses.129520.38c3=*; __zlcid=%7B%22mID%22%3A%226lcsSDyhu4rSn9%22%2C%22sid%22%3A%22130614.359848.57mMZLbH%22%7D
    User-Agent:Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.110 Safari/537.36
    Query String Parametersview sourceview URL encoded
    Response Headersview source
    Content-Type:text/html; charset=utf-8
    Date:Fri, 14 Jun 2013 21:13:42 GMT
    Via:1.1 varnish

    Normaly are the 503 error a server host prob, but I have contact they about this, and they can’t find enything that going wrong on the server.
    I have replace the controller, the index file from origine, I run the default theme.
    I even remarkt, that when I do some things, like regenerate pictures from the products, select 1 option to regenerate and tray to import and configurate the cvs file headings and click on the green button, they run even out to a blank white page, no errors to seen..

    Thanks in Advance

  5. Please guide me i am having below errors while i save cms page.
    thanks wonderful team.


    Table ‘ocsconne_snzuby.ocs_belvg_cms_search_index’ doesn’t exist

    DELETE FROM ocs_belvg_cms_search_index WHERE id_cms IN (36)

    at line 607 in file classes/db/Db.php
    601. WebserviceRequest::getInstance()->setError(500, ‘[SQL Error] ‘.$this->getMsgError().’. From ‘.(isset($dbg[3][‘class’]) ? $dbg[3][‘class’] : ”).’->’.$dbg[3][‘function’].'() Query was : ‘.$sql, 97);
    602. }
    603. else if (_PS_DEBUG_SQL_ && $errno && !defined(‘PS_INSTALLATION_IN_PROGRESS’))
    604. {
    605. if ($sql)
    606. throw new PrestaShopDatabaseException($this->getMsgError().”.$sql.”);
    607. throw new PrestaShopDatabaseException($this->getMsgError());
    608. }
    609. }
    611. /**
    DbCore->displayError – [line 307 – classes/db/Db.php] – [1 Arguments]
    DbCore->query – [line 447 – classes/db/Db.php] – [1 Arguments]
    DbCore->execute – [line 72 – override/classes/CMS.php] – [1 Arguments]
    CMS::indexation – [line 43 – override/classes/CMS.php] – [2 Arguments]
    CMS->update – [line 763 – classes/ObjectModel.php] – [1 Arguments]
    ObjectModelCore->toggleStatus – [line 349 – controllers/admin/AdminCmsController.php] – [0 Argument]
    AdminCmsControllerCore->postProcess – [line 121 – controllers/admin/AdminCmsContentController.php] – [0 Argument]
    AdminCmsContentControllerCore->postProcess – [line 158 – classes/controller/Controller.php] – [0 Argument]
    ControllerCore->run – [line 349 – classes/Dispatcher.php] – [0 Argument]
    DispatcherCore->dispatch – [line 50 – snzuby17/index.php] – [0 Argument]

  6. Hi, thanks for all you do. The following is incorrect:
    To activate a debug mode for Prestashop versions up to 1.5.3

    Should read
    To activate a debug mode for Prestashop versions below 1.5.3

  7. Hi El Patron,
    glad that you read our blog (actually I’m a fan of yours in prestashop forums ;) )

    Post is updated, hope it’s more clear now

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