I think I had the same problem. The suggestions offered herein seems to have fixed the problem that prevented the MySQL (Maria DB) server from starting. However, when using phpMyAdmin my databases seem to be present but it looks like the users that were setup for accessing the databases might be missing. I say might because when I attempt to display User Accounts in phpMyAdmin an error results as follows:
#1034 - Index for table 'db' is corrupt; try to repair it
db is one of the tables in the mysql database that was restored from the backup. Based on my interpretation of the recovery steps it is NOT too surprising to find my users missing but when User Accounts tab cannot be used it appears that there is NO way to recreate them using phpMyAdmin.
Is it possible that this problem can be resolved without starting over on XAMPP migration?