Last updated November 14, 2013. Created by tgeller on August 4, 2009.
Edited by gaele, juuuuuu, Haza, arianek. Log in to edit this page.

Links to some of the more common installation issues are listed below. More troubleshooting information is available at the Troubleshooting FAQ.

Fatal error: Allowed memory size of n bytes exhausted

The error "Allowed memory size exhausted" indicates that Drupal needs more memory than has been allocated under current settings. This error can be resolved by adding an extra line to Drupal's configuration files.

Failed to connect to your MySQL database server

The installation script cannot connect to the database. Check if the username, password and hostname that you provided are correct.

Cannot create directories 'files' or 'private'

The installation script needs permissions to create these directories inside the sites/default folder.

Cannot write to configuration files settings.php

The installation script needs permissions to write to the configuration files settings.php.

Blank page (White Screen of Death)

Occasionally the page is completely blank (No content. No errors.) This is what is sometimes referred to as the "White Screen of Death". There are several reasons why this might occur.

"Your PHP configuration only supports the SQLite database type" on the database configuration page during install

Drupal 7 now requires PHP to have the PDO (Php Data Object) extension enabled or compiled in. Older or home-brewed versions of PHP may not have this enabled by default. Check your phpinfo for the "pdo_mysql" extension, or see the instructions for enabling it. Discussion

"Fatal error: Maximum function nesting level of 'xxx' reached"

If you have Xdebug PHP extension installed on your server, you might encounter this error. The solution is simple, you will need to change/create a parameter on Xdebug configuration file :
xdebug.max_nesting_level=XXX
By default, the number is 100. Don't forget to restart Apache.
You can then proceed to installation or refresh error page to end it.

Other errors

Looking for support? Visit the Drupal.org forums, or join #drupal-support in IRC.

Comments

I'm not quite sure what to make of this page at the moment.
Most importantly it does not contain information about errors messages I encountered during my installation process.
- missing directories
- wrong permissions for manually set up directories (and I still don't know which permissions are needed, so they arenow set to 777)
- need to reset permissions for settngs.php
- long and repeated error messages about time zones

***
Missing directories and timezone errors need a faq on the the page

Permissions and settings.php are on the page now.
bekasu

I ran into an install error on Windows XP and found several posts for assistance with the same error (SMTP server response: 550 5.7.1 Unable to relay for .... in ....\includes\mail.inc on line 193. Unable to send e-mail....) Maybe someone (me?) should add a page for common Windows install errors.

Pat Johnston
Aromas, California

Getting an SSI error: recursion exceeded. Anyone know what this means

Hi,
I am getting the following error and I have seen several posts with it but none of them has a solution:

PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') ORDER BY fit DESC LIMIT 0, 1' at line 1: SELECT * FROM {menu_router} WHERE path IN ( ) ORDER BY fit DESC LIMIT 0, 1; Array ( ) in menu_get_item() (line 443 of C:\AppServ\www\drupal-7.0\includes\menu.inc).

I am trying to install Drupal 7.0 over Windows 7 64-bit (previously installed Appserv 2.6.0)
Let me know if you find any solution.
Regards,
Alejandro.

I am a beginner and I've been trying to install drupal 7.12 in my windows vista OS, i got many errors along the way and tweaking something here and there did the job. I'm pretty sure everything is as it's supposed to be now but I'm still not able to install it in my computer. After clicking "Save and Continue" in Set up database I keep getting the following error message:
Fatal error: Maximum execution time of 30 seconds exceeded in C:\Program Files\EasyPHP-5.3.2\www\drupal\includes\bootstrap.inc on line 2202

What am I doing wrong?

You could edit bootstrap.inc and increase the time but the real problem is you're using win Vista.
Download virtualbox, download debian .iso, load it up as a virtual machine and install Drupal in there. Much easier

I tweaked around some more, chaning the port in skype and all, it's working for me now.

My web hosting is Nginx+Php+mysql, the .httacces file don't work, is there any method ? i think i don't have to change my service t to Apache..

Tried to install Drupal 7 in XAMPP (xampp-win32-1.7.0) in my local system where the versions are :

ENV : Windows XP SP2
PHP Version 5.2.8
Server API Apache 2.0 Handler
PHP API 20041225
PHP Extension 20060613
Zend Extension 220060519
Apache Version Apache/2.2.11 (Win32) DAV/2 mod_ssl/2.2.11 OpenSSL/0.9.8i mod_autoindex_color PHP/5.2.8
Apache API Version 20051115

I'v tried for the minimal config, but system shows "Apache server encountered a problem and need to close", after these drupal installation disrupted with error msg "Table variable already exists. ".

Need help to debug this problem.

Adavnce thanks to you guys.