Importing a standalone address book doesn't require a restart, but Thunderbird restarts. (This happens for LDIF imports but not CSV because the CSV importer seems to always throw an error message and that prevents the restart.)

Sorry for the regression, I guess we need to add a needsRestart getter to nsIImportGeneric.idl, but then all subclasses need to implement this getter.

That would be a way to solve it, except that the .mab to .sqlite migration has been removed from the start-up process, so the import is completely broken anyway.

I think I'm going create a Mork address book importer that won't require a restart.