I have a computer that dual boots Xubuntu 16.04 & Kubuntu 16.10. I had all my ham programs on the Kubuntu partition. This morning KDE would not start. I decided to move everything to the Xubuntu partition. Everything worked except CQRLOG. I get the same errors at startup that DDOWNS described in his post of 3/23. Here is the mysql.err file from ~/.config/database:

170420 18:29:15 [Note] InnoDB: Using mutexes to ref count buffer pool pages
170420 18:29:15 [Note] InnoDB: The InnoDB memory heap is disabled
170420 18:29:15 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
170420 18:29:15 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
170420 18:29:15 [Note] InnoDB: Compressed tables use zlib 1.2.8
170420 18:29:15 [Note] InnoDB: Using Linux native AIO
170420 18:29:15 [Note] InnoDB: Using CPU crc32 instructions
170420 18:29:15 [Note] InnoDB: Initializing buffer pool, size = 80.0M
170420 18:29:15 [Note] InnoDB: Completed initialization of buffer pool
170420 18:29:15 [Note] InnoDB: Highest supported file format is Barracuda.
InnoDB: No valid checkpoint found.
InnoDB: If you are attempting downgrade from MySQL 5.7.9 or later,
InnoDB: please refer to http://dev.mysql.com/doc/refman/5.6/en/upgrading-downgrading.html
InnoDB: If this error appears when you are creating an InnoDB database,
InnoDB: the problem may be that during an earlier attempt you managed
InnoDB: to create the InnoDB data files, but log file creation failed.
InnoDB: If that is the case, please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/error-creating-innodb.html
170420 18:29:15 [ERROR] Plugin 'InnoDB' init function returned error.
170420 18:29:15 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
170420 18:29:15 [Note] Plugin 'FEEDBACK' is disabled.
170420 18:29:15 [ERROR] Unknown/unsupported storage engine: innodb
170420 18:29:15 [ERROR] Aborting

170420 18:29:15 [Note] /usr/sbin/mysqld: Shutdown complete

The web pages listed in the error file were no help.
If you could prod me in the right direction, I would appreciate it.
73,
Bill