When installing and running MySQL for the first time, you may encounter certain errors that prevent the MySQL server from starting. This section helps you diagnose and correct some of these errors.
Your first resource when troubleshooting server issues is the
error log. The MySQL server
uses the error log to record information relevant to the error
that prevents the server from starting. The error log is located
in the data directory
specified in your
my.ini file. The default
data directory location is
Server 5.5\data, or
C:\ProgramData\Mysql on Windows 7 and Windows
Server 2008. The
C:\ProgramData directory is
hidden by default. You need to change your folder options to see
the directory and contents. For more information on the error log
and understanding the content, see The Error Log.
For information regarding possible errors, also consult the console messages displayed when the MySQL service is starting. Use the NET START MySQL command from the command line after installing mysqld as a service to see any error messages regarding the starting of the MySQL server as a service. See Section 1.7.7, “Starting MySQL as a Windows Service”.
The following examples show other common error messages you might encounter when installing MySQL and starting the server for the first time:
If the MySQL server cannot find the
privileges database or other critical files, it displays these
System error 1067 has occurred. Fatal error: Can't open and lock privilege tables: Table 'mysql.user' doesn't exist
These messages often occur when the MySQL base or data
directories are installed in different locations than the
default locations (
Server 5.5 and
Files\MySQL\MySQL Server 5.5\data,
This situation can occur when MySQL is upgraded and installed to a new location, but the configuration file is not updated to reflect the new location. In addition, old and new configuration files might conflict. Be sure to delete or rename any old configuration files when upgrading MySQL.
If you have installed MySQL to a directory other than
C:\Program Files\MySQL\MySQL Server
5.5, ensure that the MySQL server is
aware of this through the use of a configuration
my.ini) file. Put the
my.ini file in your Windows directory,
C:\WINDOWS. To determine its
exact location from the value of the
environment variable, issue the following command from the
You can create or modify an option file with any text editor,
such as Notepad. For example, if MySQL is installed in
E:\mysql and the data directory is
D:\MySQLdata, you can create the option
file and set up a
[mysqld] section to
specify values for the
[mysqld] # set basedir to your installation path basedir=E:/mysql # set datadir to the location of your data directory datadir=D:/MySQLdata
Microsoft Windows path names are specified in option files using (forward) slashes rather than backslashes. If you do use backslashes, double them:
[mysqld] # set basedir to your installation path basedir=C:\\Program Files\\MySQL\\MySQL Server 5.5 # set datadir to the location of your data directory datadir=D:\\MySQLdata
The rules for use of backslash in option file values are given in Using Option Files.
If you change the
datadir value in your MySQL
configuration file, you must move the contents of the existing
MySQL data directory before restarting the MySQL server.
If you reinstall or upgrade MySQL without first stopping and removing the existing MySQL service and install MySQL using the MySQL Installer, you might see this error:
Error: Cannot create Windows service for MySql. Error: 0
This occurs when the Configuration Wizard tries to install the service and finds an existing service with the same name.
One solution to this problem is to choose a service name other
mysql when using the configuration
wizard. This enables the new service to be installed
correctly, but leaves the outdated service in place. Although
this is harmless, it is best to remove old services that are
no longer in use.
To permanently remove the old
service, execute the following command as a user with
administrative privileges, on the command line:
sc delete mysql[SC] DeleteService SUCCESS
sc utility is not available for your
version of Windows, download the
and use the
delsrv mysql syntax.