I already try that (well actually I only run "> .yappari/chats.db" and "> .yappari/roster.db" command) but Yappari still crash.

I follow your advice, downgrade to Yappari 0.25, exit all grup chat, empty .db files, install Yappari 0.26 and it's ok now.
Yappari running without crash.

But as someone previously mention, is contact search not working anymore on Yappari 0.26?