Question

I tried to change the data folder path of MySQL by changing the datadir parameter in the my.ini file. But when I restarted MySQL service again I get the following error :

Error 1067: the process terminated unexpectedly.

I checked the .err file, the following errors are present: (they are all about InnoDB)

120319  3:59:59 [Note] Plugin 'FEDERATED' is disabled.  
120319  3:59:59 InnoDB: The InnoDB memory heap is disabled  
120319  3:59:59 InnoDB: Mutexes and rw_locks use Windows interlocked functions  
120319  3:59:59 InnoDB: Compressed tables use zlib 1.2.3  
120319  3:59:59 InnoDB: Initializing buffer pool, size = 75.0M  
120319  3:59:59 InnoDB: Completed initialization of buffer pool  
InnoDB: Error: log file .\ib_logfile0 is of different size 0 99614720 bytes  
InnoDB: than specified in the .cnf file 0 39845888 bytes!  
120319  3:59:59 [ERROR] Plugin 'InnoDB' init function returned error.  
120319  3:59:59 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.  
120319  3:59:59 [ERROR] Unknown/unsupported storage engine: INNODB  
120319  3:59:59 [ERROR] Aborting  

Answer 1

You have to specify the right size for:
innodb_log_file_size=95M in your my.cnf or my.ini. It is specified as 38M currently I guess.

Also check from your data folder as how many ib_logfiles you have. If you have more than 2, specify also: innodb_log_files_in_group=2.