How to Fix MySQL “[ERROR] InnoDB: Attempted to open a previously opened tablespace.”

 

You can try this method also:

1. Open Ampps Application -> MySQL Tab -> Configuration.

2. In [mysqld] section, add the following line:
innodb_force_recovery = 1

3. Save the file and try starting MySQL

4. Remove that line which you just added and Save.

source: http://www.softaculous.com/board/index.php?tid=4584&title=MySQL_will_not_Start