Two most common reasons (and fixes) for the MySQL server has gone away (error 2006) are:

1. Server timed out and closed the connection. How to fix: check that wait_timeout variable in your mysqld’s my.cnf configuration file is large enough. On Debian: sudo nano /etc/mysql/my.cnf, set wait_timeout to at least 600 seconds (you can tweak/decrease this value when error 2006 is gone), then sudo /etc/init.d/mysql restart. I didn’t check, but the default value for wait_timeout might be around 28800 seconds (8 hours).
    
2. Server dropped an incorrect or too large packet. If mysqld gets a packet that is too large or incorrect, it assumes that something has gone wrong with the client and closes the connection. You can increase the maximal packet size limit by increasing the value of max_allowed_packet in my.cnf file. On Debian: sudo nano /etc/mysql/my.cnf, set max_allowed_packet to to something like 64M (you can tweak/decrease this value when error 2006 is gone), then sudo /etc/init.d/mysql restart.

NB:

• my.cnf might not be present so look for my.ini instead
• In xampp the file my.ini is located in %xampproot%\mysql\bin