Upgrading v8.0.12-->v8.0.13 does not work: Access denied

[Peter Steiner]

I have an existing and working MYSQL DB for v8.0.12 on 64bit Win7

Now I downloaded the newest community version MySQL 8.0.13 and installed it.

When I start the MySQL server now (with the existing data DB) I got an error:

[ERROR] [MY-013142] [Server] Column count of mysql.user is wrong. Expected 50, found 49. Created with MySQL 80012, now running 80013. Please use mysql_upgrade to fix this error.

Ok, I opened a new CommandPrompt/Terminal in MySQLs /bin subdirectory and entered:

mysql_upgrade -uroot -pmypassword

As a result I got an error as well:

mysql_upgrade: [Warning] Using a password on the command line interface can be insecure.
mysql_upgrade: Got error: 1045: Access denied for user 'root'@'localhost' (using password: YES) while connecting to the MySQL server
Upgrade process encountered error and will not continue.


I am absolutely sure that user root exists and has password "mypassword".

So why does the upgrade not work?

Peter