Column count of mysql.proc is wrong. Expected 20, found 16. The table is probably corrupted
Solution 1:
I had this error as well. I fixed it by running
mysql_upgrade -u root -p
Also, restart the mysql service by running
service mysqld restart
Solution 2:
I had the same problem when I updated XAMPP from xampp-osx-7.2.10 to 7.3.9 in MacOS Mohave. So the solution was:
Find the file mysql_upgrade in "Macintosh HD ▸ Applications ▸ XAMPP ▸ xamppfiles ▸ bin" and double click on it.
Solution 3:
This error happens when a bad upgrade is done. For example, it happens if you upgrade from 5.0 to 5.1 but don't run the mysql_upgrade script; or, in rare cases, it probably happens if you directly upgrade from 5.0 to 5.5. (Many people does this, but such updrages are not officially supported) You say you are using a hosting service - well, I think that you should create a ticket and tell them about the problem. If you don't have the SUPER privilege, there is nothing you can do. But if you have that right, simply run mysql_upgrade: http://dev.mysql.com/doc/refman/5.1/en/mysql-upgrade.html
Solution 4:
A similar error appeared in MySQL Workbench 8.0.21 after installing XAMPP 7.4.8 on Ubuntu 18.04. There were no problems using phpMyAdmin.
Error Code: 1558 Column count of mysql.proc is wrong. Expected 21, found 20. Created with MariaDB 100108, now running 100413. Please use mysql_upgrade to fix this error
Solution:
sudo /opt/lampp/lampp start
/opt/lampp/bin/mysql_upgrade
Problem solved
Credits: There appear to be a bug in XAMPP - https://community.apachefriends.org/f/viewtopic.php?f=17&t=78386&sid=3d3824dd0b6aa2e33c3adc73c744b4b4