XAMPP: MySQL shutdown unexpectedly

Rename the folder xampp/mysql/data to xamppmysql/data_bk
Create a new folder xampp/mysql/data
Copy the content that resides in xampp/mysql/backup to the new mysql/data folder
Copy all your database folders that are in xamppmysql/data_bk to xampp/mysql/data
Important: Do not copy the mysql, performance_schema, and phpmyadmin folders from xampp/mysql/data_bk
Finally copy the ibdata1 file from xampp/mysql/data_bk and replace it inside xampp/mysql/data folder
Start MySQL from XAMPP control panel