The tooltip for ""Use internal MySQL server" is just wordier rephrasing of the same "Choose whether Akonadi should Use and internal or external MySQL server.", it does not add or clarify anything. IMO what needs clarifying is "internal." Reproducible: Always
This bug has only been reported for versions older than KDEPIM 4.14 (at most akonadi-1.3). Can anyone tell if this bug still present? If noone confirms this bug for a recent version of akonadi (part of KDE Applications 15.08 or later), it gets closed in about three months.
Just as announced in my last comment, I close this bug. If you encounter it again in a recent version (at least 5.0 aka 15.08), please open a new one unless it already exists. Thank you for all your input.