How to the error message display on in case of unexpected blank pages?

In prestashop  back-office and/or front-office start displaying a blank page  or incomplete page regularly without any error message, it is necessary to activate the display of the PHP errors in order to understand the problem.

This is done in your PrestaShop installation's /config/defines.inc.php file. You should edit the following line:

define('_PS_MODE_DEV_', false);

...and change it into:

define('_PS_MODE_DEV_', true);

Now browse your store's pages again. PrestaShop will display all the relevant error messages (if any), which should help you solve the issue.

Once the issue has been fixed, you must revert your changes: edit the /config/defines.inc.php file again and put false back as the value for the_PS_MODE_DEV_ constant.

How to regenerating a password manually in prestashop

As situations where nothing happens when you request a new password, and it doesn't work. There can be a number of reasons why this would happen, but the important thing is to be able to log in prestashop user and admin again.

This is will require you to access your database, using phpMyAdmin for instance.

You will have to follow the following procedure:

1. Open the /config/settings.inc.php file, from your shop's root directory. Find the line containing "_COOKIE_KEY_". Copy the cookie content (without the quotes): it is the MD5 for your original password.
2. You now need to generate a new MD5 hash for your password:
   1. Go to http://www.miraclesalad.com/webtools/md5.php.
   2. Paste the value of "_COOKIE_KEY_" in the text-field, and right after it, add your desired password. For instance, xykxB41JrEacRIoZxDioPNRmKeuO3ixCLygNxBAkeOkAHf2YUVESuT9jMYPASSWORD, where the cookie ends with T9j, and the desired password is MYPASSWORD (it can be anything you want).
   3. Click on the "md5" button: this will produce a MD5 hash of the text-field's content. Copy it.
3. You now need to put this hash into your database:
   1. Open you shop's database using phpMyAdmin. If you don't know how to use phpMyAdmin, ask your webmaster, or your host.
   2. Open the pw_employee table, find the row corresponding to your account (it should feature your first name, last name, and e-mail address), and click its "Edit" button.
   3. Find the passwd field, and paste in the MD5 that you just generated.
4. Log in to your back-office with the email listed in the same table, and the desired password that you used above (MYPASSWORD). This will generate a new cookie key.

If it still doesn't work, use phpMyAdmin to access the ps_shop_url table and check the value of the main shop, whose id is 1. It should contain the shop's file path:

• If your shop is at the root of the server, this variable should contain "/".
• If your shop is in a sub-directory, it should contain it. For instance, if it's at "http://www.mywebsite/shop/", then the variable should contain "/shop/".

If all fails, contact the PrestaShop support team at http://support.prestashop.com/en/.

How to Debug in Prestashop - Blank page problem after install Prestashop 1.5 ?

For Debug Prestahop 1.5, set the define variable _PS_MODE_DEV_  set to 'true' on line 28 in file config/defines.inc.php. 

/* Debug only */
define('_PS_MODE_DEV_', true); 

Then,  refresh  website to see debug information. See below:  

Warning: base64_decode() has been disabled for security reasons
/home/pioneerm/public_html/prest/classes/Rijndael.php on line 35
  
its mean that, function base64_decode() should be enabled. Just contact hosting provider to confirm enabling this function

How to edit the php.ini file to fix the white screen error

1. step 1: Log into your cPanel interface.
2. step 2: Once in the cPanel, click on the File Manager icon located in the Files category.
3. step 3: Once in the File Manager navigate to the folder where PrestaShop is installed. This is normally the public_html folder.
4. step 4: Locate and then open the php.ini file for editing.
5. step 5: Scroll or search through the file and locate the memory_limit setting. It is normally set to 32M, which means 32 MB. Change the setting to something larger, say 128M.

How to create multiple shops and sub shop

Managing Multiple Shops

Multiple shop and sub shop both are same procedure 

One of the main features of PrestaShop 1.5 is called "multistore", meaning the ability to manage multiple shops from the same back-office.
Thanks to this feature, you can manage many customized shops, which share many common elements. For more efficiency, you can even create groups of shops.

How to decide if you need the multistore feature

You may find yourself wanting to use the multistore feature, when in fact it is not necessary. For instance, if you want a multilingual shop, or if you need to use more than one currency, or if you would like to have a different graphic template for each category.
Here are two questions that you should ask yourself before deciding to enable the multistore feature:

1. Do you want your shops to have a different price for the same product (besides special discounts for a client or group of clients).
   If the answer is 'yes', then you need to use the multistore feature.
2. When a client buys from one shop, would you want him or her to not have access that shop's order history and invoices from the other shop (even if the client have the same login credentials on both shops).
   If the answer is 'yes', then you need to use the multistore feature: the shops will not share their carts and orders, and customers putting items in their cart for shop 1 will not see these items in their cart for shop 2.

If the answer is 'no' to both questions, then the multistore feature is not for you.

One back-office to rule them all

When the multistore feature is enabled for your PrestaShop 1.5 installation, many aspects of PrestaShop become customizable on a per-shop or per-shop-group basis.

View more in details 

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