MySQL 5.6: creating users kills mysql, and mysq_upgrade fails

[Simon Hobbs]

I have a fresh (not upgrade) installation of mysql 5.6.19 community edition win64 running on windows 8.

I have had no problems with it until today I tried to create a new user. When I do this, mysql instantly dies with nothing in the log files.

Googling around says this can be a problem with upgrading old databases, and i need to run "msyql_upgrade". When I run this on the same pc and with the mysql root user, it simply outputs:

FATAL ERROR: Upgrade failed.

Any ideas what I can do? In my database is an import of an old legacy DB. It works fine, I can query our old data etc. I don't want to lose this.

In the log files, I only see one error which pops up occasionally without any detrimental effect:

Incorrect definition of table mysql.proc: expected column 'comment' at position 15 to have type text, found type char(64).

Any ideas how I can add users, or do the upgrade, or find out whats causing the upgrade to fail?