As it says, only old already indexed emails can be searched in krunner. The mail folders are marked full text searchable, with last index date when I recreated completely the akonadi and nepomuk databases. Using 4.9.4 on Arch. Any hints are welcome to force nepomuk re-indexing of emails. Thanks.

Found that senging a SIGHUP to akonadi_nepomuk_feeder forced re-indexing of the emails. An automatic indexing of incoming messages would be nicer of course. It remains an acceptable workaround nevertheless.

Cheers.