I just install a XAMPP 7.3.6-2-VC15 for Win64, and when i install it, it\'s fine, MySQL start from control panel without error, et all is ok.
After rebooting my PC,
I got this problem like you . I have solved this problem like below.
Copy from xampp/mysql/backup folder and paste in xampp/mysql/data folder except ibdata1 file.
If you replace ibdata1 file from xampp/mysql/data then some database you will get error table does not exist.
This one helped for me:
Open shell from from control panel and start mysql with this command:
mysqld –-console –-skip-grant-tables –-skip-external-locking
Open another shell from control panel and repair database with this command:
mysqlcheck -r --databases mysql --use-frm
Stop mysql, close shells and restart mysql normally.
based on: Re: Corrupt mysql.users How to fix