I had MySql 5.1.13 Database on Windows 2008, then on one fine day I took backup of my server [300+ databases]. Uninstall Old version and install 5.5 Version of MYSql. Now I copy the Data Folder back in Mysql 5.5 data location and I got all my Databases, but later I realise that around 250 Databases though did present at location but they do not show Tables in PHPmyadmin. I try to run “Show Tables” on couple of those database and Tables name does shows [and so as tablename.frm files exits] .
not to mention all tables that are Innodb are only one missing. How can get them back with ease. I have backup of each database but running 250 SQL files is not easy :).
Your innodb engines can have their own seperate folder where they store their data files. According the MySQL manual InnoDB creates tablespace files in the MySQL data directory by default see: http://dev.mysql.com/doc/refman/5.0/en/innodb-configuration.html.
Normally you would split you tables onto different drives to increase performance thus you might have a scenario where the InnoDB tables where configured to be placed on a another drive or folder. If you have it please check the previous MySQL configuration file and check for the following line: innodb_data_home_dir = /ibdata
This will indicate where the files are located. I have not tried this but you should be able to point the current config to the old innodb location if this is the case. If that does not work I think restoring will be you best bet.
Good luck!