I tried to upgrade to MySQL 5.5 from 5.1. When I try to run Instance Configuration Wizard I get this error:

Could not start the service MySQL. Error:0

I am to the point now that I would be happy just to have a fresh install of MySQL 5.5. I can repopulate the database after.

Things I have tried:

  1. Restart the machine and try Instance Configuration Again
  2. Uninstall all MySQL software and making sure that there was no service and reinstall
  3. search registry to make sure there was no MySQL entries.
  4. I tried to check the .err log, but there was none to be found.
  5. Googled online to see if anyone was having same issue. Several people were but there was no simple solution.
  6. Followed this guideline step by step but still no success

Information that I have:

OS: WINDOWS XP Service Pack 3

after running mysqld -nt --defaults-file="C:\Program Files\MySQL\MySQL Server 5.5\my.ini" in cmd this is outputted:

--standalone --console >>output.txt
111109 10:09:33 [Warning] option 'new': boolean value 't' wasn't recognized. Set
 to OFF.
111109 10:09:33 [Note] Plugin 'FEDERATED' is disabled.
111109 10:09:33 InnoDB: The InnoDB memory heap is disabled
111109 10:09:33 InnoDB: Mutexes and rw_locks use Windows interlocked functions
111109 10:09:33 InnoDB: Compressed tables use zlib 1.2.3
111109 10:09:33 InnoDB: Initializing buffer pool, size = 47.0M
111109 10:09:33 InnoDB: Completed initialization of buffer pool
InnoDB: Error: log file .\ib_logfile0 is of different size 0 104857600 bytes
InnoDB: than specified in the .cnf file 0 25165824 bytes!
111109 10:09:33 [ERROR] Plugin 'InnoDB' init function returned error.
111109 10:09:33 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.

111109 10:09:33 [ERROR] mysqld: unknown variable 'defaults-file=C:\Program Files
\MySQL\MySQL Server 5.5\my.ini'
111109 10:09:33 [ERROR] Aborting

111109 10:09:33 [Note] mysqld: Shutdown complete

Here is what is in my.ini:

# MySQL Server Instance Configuration File
# ----------------------------------------------------------------------
# Generated by the MySQL Server Instance Configuration Wizard
# Installation Instructions
# ----------------------------------------------------------------------
# On Linux you can copy this file to /etc/my.cnf to set global options,
# mysql-data-dir/my.cnf to set server-specific options
# (@localstatedir@ for this installation) or to
# ~/.my.cnf to set user-specific options.
# On Windows you should keep this file in the installation directory 
# of your server (e.g. C:\Program Files\MySQL\MySQL Server X.Y). To
# make sure the server reads the config file use the startup option 
# "--defaults-file". 
# To run run the server from the command line, execute this in a 
# command line shell, e.g.
# mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
# To install the server as a Windows service manually, execute this in a 
# command line shell, e.g.
# mysqld --install MySQLXY --defaults-file="C:\Program Files\MySQL\MySQL Server X.Y\my.ini"
# And then execute this in a command line shell to start the server, e.g.
# net start MySQLXY
# Guildlines for editing this file
# ----------------------------------------------------------------------
# In this file, you can use all long options that the program supports.
# If you want to know the options a program supports, start the program
# with the "--help" option.
# More detailed information about the individual options can also be
# found in the manual.
# ----------------------------------------------------------------------
# The following options will be read by MySQL client applications.
# Note that only client applications shipped by MySQL are guaranteed
# to read this section. If you want your own MySQL client program to
# honor these values, you need to specify it as an option during the
# MySQL client library initialization.




# ----------------------------------------------------------------------
# The following options will be read by the MySQL Server. Make sure that
# you have installed the server correctly (see above) so it reads this 
# file.

# The TCP/IP Port the MySQL Server will listen on

#Path to installation directory. All paths are usually resolved relative to this.
basedir="C:/Program Files/MySQL/MySQL Server 5.5/"

#Path to the database root
datadir="C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.5/Data/"

# The default character set that will be used when a new schema or table is
# created and no character set is defined

# The default storage engine that will be used when create new tables when

# Set the SQL mode to strict

# The maximum amount of concurrent sessions the MySQL server will
# allow. One of these connections will be reserved for a user with
# SUPER privileges to allow the administrator to login even if the
# connection limit has been reached.

# Query cache is used to cache SELECT results and later return them
# without actual executing the same query once again. Having the query
# cache enabled may result in significant speed improvements, if your
# have a lot of identical queries and rarely changing tables. See the
# "Qcache_lowmem_prunes" status variable to check if the current value
# is high enough for your load.
# Note: In case your tables change very often or if your queries are
# textually different every time, the query cache may result in a
# slowdown instead of a performance improvement.

# The number of open tables for all threads. Increasing this value
# increases the number of file descriptors that mysqld requires.
# Therefore you have to make sure to set the amount of open files
# allowed to at least 4096 in the variable "open-files-limit" in
# section [mysqld_safe]

# Maximum size for internal (in-memory) temporary tables. If a table
# grows larger than this value, it is automatically converted to disk
# based table This limitation is for a single table. There can be many
# of them.

# How many threads we should keep in a cache for reuse. When a client
# disconnects, the client's threads are put in the cache if there aren't
# more than thread_cache_size threads from before.  This greatly reduces
# the amount of thread creations needed if you have a lot of new
# connections. (Normally this doesn't give a notable performance
# improvement if you have a good thread implementation.)

#*** MyISAM Specific options

# The maximum size of the temporary file MySQL is allowed to use while
# recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE.
# If the file-size would be bigger than this, the index will be created
# through the key cache (which is slower).

# If the temporary file used for fast index creation would be bigger
# than using the key cache by the amount specified here, then prefer the
# key cache method.  This is mainly used to force long character keys in
# large tables to use the slower key cache method to create the index.

# Size of the Key Buffer, used to cache index blocks for MyISAM tables.
# Do not set it larger than 30% of your available memory, as some memory
# is also required by the OS to cache rows. Even if you're not using
# MyISAM tables, you should still set it to 8-64M as it will also be
# used for internal temporary disk tables.

# Size of the buffer used for doing full table scans of MyISAM tables.
# Allocated per thread, if a full scan is needed.

# This buffer is allocated when MySQL needs to rebuild the index in
# REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE
# into an empty table. It is allocated per thread so be careful with
# large settings.

#*** INNODB Specific options ***

# Use this option if you have a MySQL server with InnoDB support enabled
# but you do not plan to use it. This will save memory and disk space
# and speed up some things.

# Additional memory pool that is used by InnoDB to store metadata
# information.  If InnoDB requires more memory for this purpose it will
# start to allocate it from the OS.  As this is fast enough on most
# recent operating systems, you normally do not need to change this
# value. SHOW INNODB STATUS will display the current amount used.

# If set to 1, InnoDB will flush (fsync) the transaction logs to the
# disk at each commit, which offers full ACID behavior. If you are
# willing to compromise this safety, and you are running small
# transactions, you may set this to 0 or 2 to reduce disk I/O to the
# logs. Value 0 means that the log is only written to the log file and
# the log file flushed to disk approximately once per second. Value 2
# means the log is written to the log file at each commit, but the log
# file is only flushed to disk approximately once per second.

# The size of the buffer InnoDB uses for buffering log data. As soon as
# it is full, InnoDB will have to flush it to disk. As it is flushed
# once per second anyway, it does not make sense to have it very large
# (even with long transactions).

# InnoDB, unlike MyISAM, uses a buffer pool to cache both indexes and
# row data. The bigger you set this the less disk I/O is needed to
# access data in tables. On a dedicated database server you may set this
# parameter up to 80% of the machine physical memory size. Do not set it
# too large, though, because competition of the physical memory may
# cause paging in the operating system.  Note that on 32bit systems you
# might be limited to 2-3.5G of user level memory per process, so do not
# set it too high.

# Size of each log file in a log group. You should set the combined size
# of log files to about 25%-100% of your buffer pool size to avoid
# unneeded buffer pool flush activity on log file overwrite. However,
# note that a larger logfile size will increase the time needed for the
# recovery process.

# Number of threads allowed inside the InnoDB kernel. The optimal value
# depends highly on the application, hardware as well as the OS
# scheduler properties. A too high value may lead to thread thrashing.

Things that I tried since posting:

  1. tried to delete both ib_logfile0 and ib_logfile1 but they did not exist
  2. ran 'mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server 5.5\my.ini" --nt' instead of mysqld -nt --defaults-file="C:\Program Files\MySQL\MySQL Server 5.5\my.ini but nothing outputted to screen and I still cannot get service to run
up vote 3 down vote accepted

I gave Richard a hand with this problem IRL - the problem turns out to be the MySQL directory under Application Data.

In this case: C:\Documents and Settings\All Users\Application Data\MySQL (for those not sure what I'm talking about, the equivalent path will be different under Vista/7)

Solution was to remove instance, uninstall MySQL, delete the MySQL directory under Application Data and then reinstall as mentioned in at the bottom of this thread by Eric Eskildsen and Matthew Sadowski.


It's worth noting that there was a MySQL Server 5.1 directory under the MySQL folder as well, whether it was reading that directory instead of the 5.5 or if the files in the 5.5 directory were corrupt...I don't know, but one or both of them were the culprit in this case.

Definitely, one of the weirder problems I've run across when installing MySQL :-S

  • Thanks again for your help. It would seem that I am a magnet for the "weirder problems" – Richard Nov 14 '11 at 14:57
  • Heh - no problem brother - ask Eric about some of the doozies Ron has conjured, this was minor in comparison :) – Crazy Joe Malloy Nov 18 '11 at 1:57

try to run:

mysqld --defaults-file="C:\Program Files\MySQL\MySQL Server 5.5\my.ini" --nt

it will work. the issue is that the Defaults file parameter should be the FIRST one. as mentioned here: http://dev.mysql.com/doc/refman/5.0/en/mysqld-safe.html

Edit: There were missing quotes as well in the command.

  • I tried as you said but nothing is printed in cmd and service still won't start – Richard Nov 9 '11 at 14:15
  • have you added "--standalone --console" to command line? – Farhan Nov 9 '11 at 14:22
  • Also add "--debug" to the command line which will add debug log to C:\mysqld.trace. then it can give us more detail that why it is failing. – Farhan Nov 9 '11 at 14:24
  • still nothing... – Richard Nov 9 '11 at 14:33
  • Here is another workaround: serverfault.com/questions/104014/… – Farhan Nov 9 '11 at 14:39

Your Answer


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.