Is possible to mysql change some engine tables automatically?
SHOW VARIABLES LIKE `%engine%`;


Of interest are default_storage_engine, which was MyISAM in older versions, but is now InnoDB.  This comes into play when you do CREATE TABLE without including ENGINE=....

Also of interest is enforce_storage_engine.  This strengthens the previous setting by not letting you create a table of Engine other than the default.

When changing (ALTER TABLE .. ENGINE=..) a table from one engine to another, there are some number of potential pitfalls.  I cover MyISAM --> InnoDB in here.

Did you recently upgrade MySQL?  If so, any number of problems can occur if the upgrade failed to run mysql_upgrade.

What version of MySQL are you running?

Please provide the recent contents of mysqld.err.

Please provide ls -ld /tmp

Are you using RoundCube?  The bug seems to be related to their installation.