Vacuuming your Mail.app index still works wonders
brettterpstra.com//2012/09/15/vacuuming-your-mail-app-index-still-works-wonders
What Jamie wrote
Great tip for keeping Mail.app running tip-top.
There was atip on Hawk Wings long ago which showed how to speed up Apples Mail.app by vacuuming the SQLite3 index. Ihadnt tried it since Snow Leopard, but Iwas having some serious issues with the time it took to open aMail folder on my Air, so Ithought Id give it ashot.