This frightening message can happen after a fresh installation or update of your WordPress blog. Although understanding the issue itself may be a bit advanced for the scope of this article, the fix is easy, even for those not well versed in MySQL, php or even just the stuff going on under the hood of a WordPress installation.
The message will look like this
Fatal error: Allowed memory size of 8388608 bytes exhausted (tried to allocate 143 bytes) in /home/your-directory-path…
In order to fix this, you will need to access your WordPress files by way of an ftp client. I like Filezilla , a free download, but any ftp client will do.
Once you are in your public_html directory, navigate to the folder that contains your WordPress installation and look for a file called wp-settings.php. Download that file to your desktop and open it in Notepad. Scanning down a few lines you will see something that reads:
if ( !defined('WP_MEMORY_LIMIT') )
You simply change the 32 to 64M which will give tell your server to allot more headroom for doing what it has to do. Save the file (do not rename it, and make sure you did this in Notepad or a proper code editor like Morphon or Dreamweaver; Wordpad might append a .txt extension which you don’t want.)
Now drag and drop the saved version of your updated file back into the directory on the server where you found it. You will be asked whether you want to overwrite the file. Say yes.